I learned Photoshop from scratch too. It's very daunting to start with a blank white window in front of you.
Something to remember is that everyone learns better by doing. I bought a couple of Photoshop books but it was all theoretical and ultimately, useless because I couldn't get my head around the basics. It can be the same with the millions of online tutorials out there. Where to start? What finally got me going was that I wanted to learn how to make a banner, and I sat down and did it.
So my advice is: make a list of the things you want to create, and the features you've seen elsewhere that you like. Then search google for "Photoshop tutorial" and a couple of key phrases. Hopefully you'll find a step-by-step lesson that you can physically do for yourself.
A few sites that I have in my bookmarks:
http://www.photoshop101.com/
http://www.purephotoshop.com/browse....gory=Photoshop
http://www.photoshopcafe.com/tutorials.htm
http://www.spoono.com/photoshop/tutorials/