Try
Free Ringtones, Wallpapers, Videos, Games - FunForMobile. Also
Sprint Users - Sprint PCS Forum, Downloads and Tools has alot of user-contributed ringtones and wallpapers that you can upload/download for free using the Focus Uploader or if you go to the first link, they have an uploader as well.
Like Nina stated, make sure you have some sort of Power Vision (internet) access on your phone or else you will get charged per KB of usage I think it is and it can get very costly. I've read countless threads about people wondering why their $55 bill is now over $1000 (no lie). I've seen it as bad as $6000 cuz some guy "didnt know" what he was doing. So please be careful...