besides the apple one
www.iphoneapplicationlist.com
www.modmyifone.com/apps
I use the apple one and these two. They have some good ones.
http://launchrz.com is optimized for iPhone/iPod touch, allows full searching (unlike apple’s), and also let’s you collect your favorites on a quick start page.
the largest and oldest is www.appsafari.com, fast and uncluttered interface