This is weird little blog post because I'm going to recommend you join an association that I'm not renewing my membership with. The National Association of Photoshop Professionals has been a fantastic resource for me over the past four years. The benefits of membership are enormous: written and video tutorials, a rich community forum, discounts, perks, a subscription to the excellent Photoshop User magazine, and so much more. I'm proud to have been a member.
My membership expired this month, and I'm sad to say that I'm not renewing. I know that's not exactly a ringing endorsement, but all I can say is that I've used Photoshop for maybe three projects in the past year – two of them logos (which I should be doing in Illustrator anyway). So, NAPP, it's not you, it's me. I'm not taking advantage of everything you have to offer… but I hope that anyone who uses Photoshop regularly will.
In my experience, there is no better resource for learning Photoshop at all levels from beginner to expert. For $99/year you can't beat it.