Tutorials tutorials and more tutorials!!
I found one of the best ways to learn photoshop is to pop to a newsagent and pick up one of those magazines you see there - can't think of the names of any but they normally have a load of tutorials, and come with a cd with the source imagery on it.
I learnt so much from doing these, especially at the beginning. You just follow them step by step - I find them easier than video tutorials, and they are so great for learning the basics.
Once you've got a feel for it everything starts to fall into place.
A brilliant website for tutorials is:http://psd.tutsplus.com/
It's a matter of browsing through them, finding one that catches your eye and just going for it. I know my way around photoshop like the back of my hand, and I never tire of tutorials.
I'm just heading out the door but if I think of any other websites later I'll pop back in and update.