It depends on what you want to do with it. Art, coloring, etc. or Photography manipulation. Eitherway, run over to polykarbon.com and check out their link and tutorial section. Back in the day, thats where I started. It helped me a lot to imitate others work and see how close I could get.
Scott Kelby has a great one for digital Photography
the Photoshop CS2 Book For Digital Photographers
I believe he also has a conventional one as well. Try and find one that has a tutorial disc or a place on the internet that allows you to download tutorials and follow along. That's the way Kelby does his CS2 Photography book...