=== modified file 'includes/common.inc'
--- includes/common.inc	2007-09-12 18:29:31 +0000
+++ includes/common.inc	2007-09-20 22:00:46 +0000
@@ -881,6 +881,30 @@ function format_rss_channel($title, $lin
 }
 
 /**
+ * Convert relative URLs in a block of HTML to absolute URLs.
+ *
+ * @param $html
+ *   A chunk of html.
+ * @return
+ *   The same HTML with URL in <a href=""> and  <... src=""> attributes
+ *   changed to absolute.
+ */
+function drupal_create_absolute_urls($url) {
+  global $base_url;
+  // Relative URLs.
+  $src = '%( href| src)="(?!\w+://)([^/][^"]*)"%';
+  $dst = '$1="'. $base_url .'/$2"';
+  $url = preg_replace($src, $dst, $url);
+
+  // URLs that are relative to the root.
+  $src = '%( href| src)="(?!\w+://)/?([^"]*)"%';
+  $dst = '$1="'. $base_url .'/$2"';
+  $url = preg_replace($src, $dst, $url);
+
+  return $url;
+}
+
+/**
  * Format a single RSS item.
  *
  * Arbitrary elements may be added using the $args associative array.
@@ -889,7 +913,7 @@ function format_rss_item($title, $link, 
   $output = "<item>\n";
   $output .= ' <title>'. check_plain($title) ."</title>\n";
   $output .= ' <link>'. check_url($link) ."</link>\n";
-  $output .= ' <description>'. check_plain($description) ."</description>\n";
+  $output .= ' <description>'. check_plain(drupal_create_absolute_urls($description, $link)) ."</description>\n";
   $output .= format_xml_elements($args);
   $output .= "</item>\n";