Just been going through this process myself. I usually use Fireworks, but wanted to learn Photoshop since there are so many more resources available. Here's some that I've found helpful:
- http://365psd.com/ and http://designmoo.com/ - Both have free, high-quality (for the most part) PSD's you can download. Sometimes for me the most helpful thing is just seeing how someone else constructed something. How many layers they used, which layer styles created a certain effect, etc.
- http://methodandcraft.com/ - Just recently launched, but already has some nice videos I've learned a lot from.
- http://365psd.com/ and http://designmoo.com/ - Both have free, high-quality (for the most part) PSD's you can download. Sometimes for me the most helpful thing is just seeing how someone else constructed something. How many layers they used, which layer styles created a certain effect, etc.
- http://methodandcraft.com/ - Just recently launched, but already has some nice videos I've learned a lot from.
- http://photoshopetiquette.com/ - A bunch of quick tips
- http://bjango.com/articles/ - All the design articles are great
- http://designthencode.com/ - Can't vouch for this personally as I haven't gone through it myself, but looks like a really great and detailed guide.