It's been a real struggle finding good web sites that are available on a mobile phone.  I've used the My Yahoo! site almost exclusively for quite some time now as it has several of the features that I use... movie times, web search, among other things.  I thought I'd put a list of sites together:

Favorites

Yahoo http://home.mobile.yahoo.com/
Google http://www.google.com/wml
Froogle http://wml.froogle.com
Mapquest http://www.mapquest.com/pda/main.adp


WAP/WML Portal Sites

http://www.pdaportal.com/
http://www.skweezer.net/
http://209.221.153.18/smallsites/
http://treo1.com/
http://mobile.treobits.com/
http://www.glida.net/treo.htm
http://www.thephonecam.com/links.html


WAP Directories

http://mobile.yahoo.com/resource_center/wapdir/home
http://www.wapcatalog.com/