to see a lot of cool stuff about Photoshop (and other art with other tools) check out this forum:
www.cgtalk.com
Some of the work is MIND BOGGLING....
I don't much about the forums, but you should be able to get in touch with people one on one, if that's your thing.
Also, if you want to practice entering free contests and see how you compare to others, try this:
www.worth1000.com