Just in case anyone is missing this remarkably cool site, I'll just go ahead and link it.
http://www.animeonline.net/
In my eyes, this is the Google of the anime/game wallpaper world (obviously geared more towards anime, though). Anyone who wants to try out their 'leet wallpaper making skills can go ahead and register to upload their stuff to their server.
Unfortunately this came with a pretty high cost eventually when too many people started putting their works up, and they limited DLs to only the weekends.
Still, it's a very well maintained site, and I recommend you drop on by.