Here are a few direct links to get you started:
http://www.good-tutorials.com/ - HUGE Photoshop database with lots of decent tutorials
http://www.teamphotoshop.com/ - If you go to the forums, the guys there are pretty friendly and are willing to help you out on any tutorial. If you see an image on the Internet that looks pretty cool, but don't know how it was made, the guys at TP will help you out.