If all the items are pointing to the same network share, you could search the URL attribute, then hold down Alt when clicking on a result to prevent the item document from loading, then edit the URL attribute as needed.
http://www.kinook.com/UltraRecall/Ma...etailspane.htm
Or see the SQL interface for making mass changes to an attribute.
http://www.kinook.com/Forum/showthread.php?t=2825