Funny you should mention this. I am in the process of doing a simple avatar manager site that allows rotating avatars and such. That might not be up for a bit, though.

The one I have for my avatar is very simple; it just gets a list of files in a directory and randomly picks one to return. OK, well, it's a little more complicated than that, but either way the PHP for it is simple. I'll see about cleaning it up if you want it.