diff --git a/wp-admin/admin-header.php b/wp-admin/admin-header.php
index 599be92fe1..b0b28a2c7f 100644
--- a/wp-admin/admin-header.php
+++ b/wp-admin/admin-header.php
@@ -29,14 +29,13 @@ get_admin_page_title();
 <meta http-equiv="Content-Type" content="<?php bloginfo('html_type'); ?>; charset=<?php echo get_option('blog_charset'); ?>" />
 <title><?php bloginfo('name') ?> &rsaquo; <?php echo wp_specialchars( strip_tags( $title ) ); ?> &#8212; WordPress</title>
 <?php
+
 wp_admin_css( 'css/global' );
 wp_admin_css();
 wp_admin_css( 'css/colors' );
+wp_admin_css( 'css/ie' );
+
 ?>
-<!--[if gte IE 6]>
-<?php wp_admin_css( 'css/ie' );
-?>
-<![endif]-->
 <script type="text/javascript">
 //<![CDATA[
 addLoadEvent = function(func) {if (typeof jQuery != "undefined") jQuery(document).ready(func); else if (typeof wpOnload!='function'){wpOnload=func;} else {var oldonload=wpOnload; wpOnload=function(){oldonload();func();}}};
diff --git a/wp-includes/class.wp-scripts.php b/wp-includes/class.wp-scripts.php
index 8d45f51511..d829c8e002 100644
--- a/wp-includes/class.wp-scripts.php
+++ b/wp-includes/class.wp-scripts.php
@@ -55,7 +55,7 @@ class WP_Scripts extends WP_Dependencies {
 		}
 
 		$src = add_query_arg('ver', $ver, $src);
-		$src = clean_url(apply_filters( 'script_loader_src', $src ));
+		$src = clean_url(apply_filters( 'script_loader_src', $src, $handle ));
 
 		$this->print_scripts_l10n( $handle );
 
diff --git a/wp-includes/class.wp-styles.php b/wp-includes/class.wp-styles.php
index 45dc091103..f6a6d79c35 100644
--- a/wp-includes/class.wp-styles.php
+++ b/wp-includes/class.wp-styles.php
@@ -3,6 +3,7 @@
 class WP_Styles extends WP_Dependencies {
 	var $base_url;
 	var $default_version;
+	var $text_direction = 'ltr';
 
 	function __construct() {
 		do_action_ref_array( 'wp_default_styles', array(&$this) );
@@ -21,15 +22,25 @@ class WP_Styles extends WP_Dependencies {
 		else
 			$media = 'all';
 
-		$src = $this->registered[$handle]->src;
-		if ( !preg_match('|^https?://|', $src) ) {
-			$src = $this->base_url . $src;
+		$href = $this->_css_href( $this->registered[$handle]->src, $ver, $handle );
+
+		$end_cond = '';
+		if ( isset($this->registered[$handle]->extra['conditional']) && $this->registered[$handle]->extra['conditional'] ) {
+			echo "<!--[if {$this->registered[$handle]->extra['conditional']}]>\n";
+			$end_cond = "<![endif]-->\n";
 		}
 
-		$src = add_query_arg('ver', $ver, $src);
-		$src = clean_url(apply_filters( 'style_loader_src', $src ));
+		echo apply_filters( 'style_loader_tag', "<link rel='stylesheet' href='$href' type='text/css' media='$media' />\n", $handle );
+		if ( 'rtl' === $this->text_direction && isset($this->registered[$handle]->extra['rtl']) && $this->registered[$handle]->extra['rtl'] ) {
+			if ( is_bool( $this->registered[$handle]->extra['rtl'] ) )
+				$rtl_href = str_replace( '.css', '-rtl.css', $href );
+			else
+				$rtl_href = $this->_css_href( $this->registered[$handle]->extra['rtl'], $ver, "$handle-rtl" );
 
-		echo "<link rel='stylesheet' href='$src' type='text/css' media='$media' />\n";
+			echo apply_filters( 'style_loader_tag', "<link rel='stylesheet' href='$rtl_href' type='text/css' media='$media' />\n", $handle );
+		}
+
+		echo $end_cond;
 
 		// Could do something with $this->registered[$handle]->extra here to print out extra CSS rules
 //		echo "<style type='text/css'>\n";
@@ -46,4 +57,15 @@ class WP_Styles extends WP_Dependencies {
 			$this->to_do = apply_filters( 'print_styles_array', $this->to_do );
 		return $r;
 	}
+
+	function _css_href( $src, $ver, $handle ) {
+		if ( !preg_match('|^https?://|', $src) ) {
+			$src = $this->base_url . $src;
+		}
+
+		$src = add_query_arg('ver', $ver, $src);
+		$src = apply_filters( 'style_loader_src', $src, $handle );
+		return clean_url( $src );
+	}
+
 }
diff --git a/wp-includes/general-template.php b/wp-includes/general-template.php
index 8d9b4d8941..bd2727bf9a 100644
--- a/wp-includes/general-template.php
+++ b/wp-includes/general-template.php
@@ -1131,19 +1131,7 @@ function wp_admin_css_uri( $file = 'wp-admin' ) {
 	if ( defined('WP_INSTALLING') ) {
 		$_file = "./$file.css";
 	} else {
-		if ( 'css/colors' == $file || 'css/colors-rtl' == $file ) {
-			global $_wp_admin_css_colors;
-			$color = get_user_option('admin_color');
-			if ( empty($color) || !isset($_wp_admin_css_colors[$color]) )
-				$color = 'fresh';
-			$color = $_wp_admin_css_colors[$color];
-			$_file = $color->url;
-			$_file = ('css/colors-rtl' == $file) ? str_replace('.css','-rtl.css',$_file) : $_file;
-		} elseif ( 'css/thickbox' == $file ) {
-			$_file = get_option( 'siteurl' ) . "/wp-includes/js/thickbox/thickbox.css";
-		} else {
-			$_file = get_option( 'siteurl' ) . "/wp-admin/$file.css";
-		}
+		$_file = get_option( 'siteurl' ) . "/wp-admin/$file.css";
 	}
 	$_file = add_query_arg( 'version', get_bloginfo( 'version' ),  $_file );
 
@@ -1151,12 +1139,23 @@ function wp_admin_css_uri( $file = 'wp-admin' ) {
 }
 
 function wp_admin_css( $file = 'wp-admin' ) {
+	global $wp_styles;
+	if ( !is_a($wp_styles, 'WP_Styles') )
+		$wp_styles = new WP_Styles();
 
-	echo apply_filters( 'wp_admin_css', "<link rel='stylesheet' href='" . wp_admin_css_uri( $file ) . "' type='text/css' />\n", $file );
-	if ( 'rtl' == get_bloginfo( 'text_direction' ) ) {
-		$rtl = ( 'wp-admin' == $file ) ? 'rtl' : "$file-rtl";
-		echo apply_filters( 'wp_admin_css', "<link rel='stylesheet' href='" . wp_admin_css_uri( $rtl ) . "' type='text/css' />\n", $rtl );
+	$handle = 0 === strpos( $file, 'css/' ) ? substr( $file, 4 ) : $file;
+
+	if ( $wp_styles->query( $handle ) ) {
+		if ( did_action( 'wp_print_styles' ) ) // we already printed the style queue.  Print this one immediately
+			wp_print_styles( $handle );
+		else // Add to style queue
+			wp_enqueue_style( $handle );
+		return;
 	}
+
+	echo apply_filters( 'wp_admin_css', "<link rel='stylesheet' href='" . clean_url( wp_admin_css_uri( $file ) ) . "' type='text/css' />\n", $file );
+	if ( 'rtl' == get_bloginfo( 'text_direction' ) )
+		echo apply_filters( 'wp_admin_css', "<link rel='stylesheet' href='" . clean_url( wp_admin_css_uri( "$file-rtl" ) ) . "' type='text/css' />\n", "$file-rtl" );
 }
 
 function add_thickbox() {
diff --git a/wp-includes/script-loader.php b/wp-includes/script-loader.php
index ecbb610552..25d2cdeb66 100644
--- a/wp-includes/script-loader.php
+++ b/wp-includes/script-loader.php
@@ -6,7 +6,7 @@ require( ABSPATH . WPINC . '/functions.wp-scripts.php' );
 require( ABSPATH . WPINC . '/class.wp-styles.php' );
 require( ABSPATH . WPINC . '/functions.wp-styles.php' );
 
-function wp_default_scripts( $scripts ) {
+function wp_default_scripts( &$scripts ) {
 	$scripts->base_url = get_option( 'siteurl' );
 	$scripts->default_version = get_bloginfo( 'version' );
 
@@ -203,6 +203,35 @@ function wp_default_scripts( $scripts ) {
 	}
 }
 
+function wp_default_styles( &$styles ) {
+	$styles->base_url = get_option( 'siteurl' );
+	$styles->default_version = get_bloginfo( 'version' );
+	$styles->text_direction = 'rtl' == get_bloginfo( 'text_direction' ) ? 'rtl' : 'ltr';
+
+	$rtl_styles = array( 'global', 'colors', 'dashboard', 'ie', 'install', 'login', 'media', 'theme-editor', 'upload', 'widgets' );
+
+	$styles->add( 'wp-admin', '/wp-admin/wp-admin.css' );
+	$styles->add_data( 'wp-admin', 'rtl', '/wp-admin/rtl.css' );
+
+	$styles->add( 'ie', '/wp-admin/css/ie.css' );
+	$styles->add_data( 'ie', 'conditional', 'gte IE 6' );
+
+	$styles->add( 'colors', true ); // Register "meta" stylesheet for admin colors
+
+	$styles->add( 'global', '/wp-admin/css/global.css' );
+	$styles->add( 'media', '/wp-admin/css/media.css' );
+	$styles->add( 'widgets', '/wp-admin/css/widgets.css' );
+	$styles->add( 'dashboard', '/wp-admin/css/dashboard.css' );
+	$styles->add( 'install', '/wp-admin/css/install.css' );
+	$styles->add( 'theme-editor', '/wp-admin/css/theme-editor.css' );
+	$styles->add( 'press-this', '/wp-admin/css/press-this.css' );
+	$styles->add( 'thickbox', '/wp-includes/js/thickbox/thickbox.css' );
+	$styles->add( 'login', '/wp-admin/css/login.css' );
+
+	foreach ( $rtl_styles as $rtl_style )
+		$styles->add_data( $rtl_style, 'rtl', true );
+}
+
 function wp_prototype_before_jquery( $js_array ) {
 	if ( false === $jquery = array_search( 'jquery', $js_array ) )
 		return $js_array;
@@ -232,6 +261,31 @@ function wp_just_in_time_script_localization() {
 	) );
 }
 
+function wp_style_loader_src( $src, $handle ) {
+	if ( defined('WP_INSTALLING') )
+		return preg_replace( '#^wp-admin/#', './', $src );
+
+	if ( 'colors' == $handle || 'colors-rtl' == $handle ) {
+		global $_wp_admin_css_colors;
+		$color = get_user_option('admin_color');
+		if ( empty($color) || !isset($_wp_admin_css_colors[$color]) )
+			$color = 'fresh';
+		$color = $_wp_admin_css_colors[$color];
+		$parsed = parse_url( $src );
+		$url = $color->url;
+		if ( isset($parsed['query']) && $parsed['query'] ) {
+			wp_parse_str( $parsed['query'], $qv );
+			$url = add_query_arg( $qv, $url );
+		}
+		return $url;
+	}
+
+	return $src;
+}
+
 add_action( 'wp_default_scripts', 'wp_default_scripts' );
 add_filter( 'wp_print_scripts', 'wp_just_in_time_script_localization' );
 add_filter( 'print_scripts_array', 'wp_prototype_before_jquery' );
+
+add_action( 'wp_default_styles', 'wp_default_styles' );
+add_filter( 'style_loader_src', 'wp_style_loader_src', 10, 2 );