In reply to Duncan Campbell: I havent done it in a while, but from what i remember you're meant to send them off just before/after theyve gone through. If you let any holes get too big i think it can be quite hard for the person resoling the shoe to keep the shape of the show.
As to whether its worth it, it largely depends on how good a job the person resoling the shoe does. However, even if they do a perfect job your shoes wont be the same and generally wont be as good as a new pair.
Feet first (the chesterfield one) generally get decent reviews, along with Chesire Shoes. More info here:
http://ukbouldering.com/board/index.php/topic,17127.msg303168/boardseen.htm...