=== modified file 'wp-admin/import/wordpress.php'
--- wp-admin/import/wordpress.php	2009-08-06 19:23:20 +0000
+++ wp-admin/import/wordpress.php	2009-08-06 19:51:00 +0000
@@ -551,7 +551,7 @@
 		// the filter can return false to skip a particular metadata key
 		$_key = apply_filters('import_post_meta_key', $key);
 		if ( $_key ) {
-			add_post_meta( $post_id, $_key, $value );
+		  add_post_meta( $post_id, $_key, $value, false, false );
 			do_action('import_post_meta', $post_id, $_key, $value);
 		}
 	}

=== modified file 'wp-includes/post.php'
--- wp-includes/post.php	2009-08-06 19:23:20 +0000
+++ wp-includes/post.php	2009-08-06 19:33:33 +0000
@@ -510,7 +510,7 @@
  * @param bool $unique Optional, default is false. Whether the same key should not be added.
  * @return bool False for failure. True for success.
  */
-function add_post_meta($post_id, $meta_key, $meta_value, $unique = false) {
+function add_post_meta($post_id, $meta_key, $meta_value, $unique = false, $serialize = true) {
 	if ( !$meta_key )
 		return false;
 
@@ -526,7 +526,8 @@
 	if ( $unique && $wpdb->get_var( $wpdb->prepare( "SELECT meta_key FROM $wpdb->postmeta WHERE meta_key = %s AND post_id = %d", $meta_key, $post_id ) ) )
 		return false;
 
-	$meta_value = maybe_serialize( stripslashes_deep($meta_value) );
+	$meta_value = stripslashes_deep($meta_value);
+	if ($serialize) $meta_value = maybe_serialize($meta_value);
 
 	$wpdb->insert( $wpdb->postmeta, compact( 'post_id', 'meta_key', 'meta_value' ) );