Not free in case that's a factor, but I've found NAPP (National Association of Photoshop Users) to be a great resource in many ways. The free 3-day shipping from B&H alone has probably paid for my membership dues.
The forums there are OK, I think... I've spent little time there so far.
I'll second the NAPP recommendation. There are some gifted PS users that are able to answer just about any question you might have. It's a friendly environment, as well. Membership in NAPP has quite a few perks, including a great magazine, discounts on software and hardware and other things, great tutorials.
I've been futzing around with PS for almost 6 years now. During that time I've been involved in many PS forums. If your PS interest is photography-based, the best is DPReview's Retouching forum. It's very active and filled with knowledgeable and creative people...and it's free :-)
