diff --git a/shurly.module b/shurly.module
index 9e7da16..521a134 100644
--- a/shurly.module
+++ b/shurly.module
@@ -984,3 +984,54 @@ function _shurly_language_stub() {
   }
   return $language;
 }
+
+/**
+ * Implementation of hook_filter().
+ */
+function shurly_filter($op, $delta = 0, $format = -1, $text = '') {
+  switch ($op) {
+    case 'list':
+      return array(0 => t("Shorten all outgoing URL's"));
+
+    case 'description':
+      return t('Shorten all outgoing URL\'s.');
+
+    case 'settings':
+      break;
+
+    case 'no cache':
+      break;
+
+    case 'prepare':
+      return $text;
+
+    case 'process':
+     return _shurly_filter_process($text);
+    
+    default:
+      return $text;
+  }
+}
+
+/**
+ * Process callback for shurly filter.
+ */
+function _shurly_filter_process($text) {
+  // Find all a tags containing a full URL.
+  preg_match_all('/<a[^>]*href="(http[^"]*)"[^>]*>/i', $text, $links);
+  if (!empty($links)) {
+    $links = $links[1];
+    foreach ($links as $key => $link) {
+      $short_url = shurly_shorten($link);
+      $text = str_replace('"' . $link . '"', '"' . $short_url['shortUrl'] . '"', $text);
+    }
+  }
+  return $text;
+}
+
+/**
+ * Implements hook_filter_tips().
+ */
+function shurly_filter_tips($filter, $format, $long = FALSE) {
+  return t('All links starting with http or https will be replaced.');
+}