www.appleopolis.com has a very nice list of apps as well as a way to make a page for the apps you pick. It doesn't have a tested on itouch category. I would guess the non hacked apps iPhone apps would work on the iPod touch.
I think you just convinced my mom to buy a touch She's going on vacation and before the new apps were available I told her not to bother because she uses outlook and wouldn't be able to check her email... but since the apps came out I was like, yeah definitely buy it now... and today she was like, well does it have instant messaging and I said no, but then I did a search on here figuring there was something, and showed her on my touch how I could use beejive.com and I'm pretty sure now she'll get one!