Index: /Users/denis/Sites/sem-pro/wp-includes/link-template.php
===================================================================
--- /Users/denis/Sites/sem-pro/wp-includes/link-template.php	(revision 656)
+++ /Users/denis/Sites/sem-pro/wp-includes/link-template.php	(working copy)
@@ -1521,4 +1521,32 @@
 	return $url;
 }
 
+/**
+ * Retrieve the url to an individual plugin.
+ *
+ * @package WordPress
+ * @since 2.8.0
+ *
+ * @param string $plugin. The plugin's file, i.e. __FILE__.
+ * @return string the plugin's url link (without a trailing slash).
+*/
+function plugin_url($plugin) {
+	static $plugins_url;
+	
+	if ( !isset($plugins_url) ) {
+		$plugins_url = plugins_url();
+	}
+	
+	$plugin = dirname($plugin);
+	
+	// special: check if plugin is residing in a folder called plugin
+	if ( basename($plugin) == basename($plugins_url) && basename(dirname($plugin)) != basename($plugins_url) ) {
+		$url = $plugins_url;
+	} else {
+		$url = $plugins_url . '/' .  basename($plugin);
+	}
+
+	return $url;
+}
+
 ?>