I dont use one but I would check the apps on Apple.com. I have seen some on their. After you get there click on Iphone and then on the right it will say top apps or something like that. You can click on that and browse the apps by category.

http://www.apple.com/webapps/ is your direct url link – webapps for iphone are available to use on ipod touch.

i did come across some books to read on the iphone = Jules Verne’s novel Five Weeks in a Balloon formatted for the iPhone. http://www.apple.com/webapps/entertainment/fiveweeksinaballoon.html

all things iphone related – check out http://www.iphoneatlas.com/