If you don't mind paying CleanApp 3 is the best of the bunch
http://www.synium.de/products/cleanapp/index.html
http://www.synium.de/products/cleanapp/index.html
I just tested a few of these, using Skype.app as the file to be deleted.
AppZapper found 4 items
AppCleaner found 6 items
AppDelete found 9 items
EasyFind found 16 items
Finder found 17 items
I just tried it. What a pain! First, it leaves behind cache folders and other files, like the others, so it's not very thorough. Also, it doesn't list the files and locations first, so you can choose what to delete. It just moves the files it finds to the Trash. On Leopard, there's no way to know where the files came from, so if you change your mind, you can't easily put them back where they came from.Have you ever tried AppTrap?