I posted this on cast boolits but I figured I would toss it up here too in case it might help someone, and since this forum is where I got my start...
I set out some of the common types of wheel weights I have encountered, here is a picture that may help others differentiate between types.
Also a video but the picture is clearer: http://www.youtube.com/watch?v=oeOz63v4eYM
Another video about hand sorting WW: http://www.youtube.com/watch?v=rZxa43_9C9M
I'm fairly new to this stuff too but hopefully this info can help some people just starting out.