As for not having Photoshop, there is a free graphics program available, called GIMP. I have *no* experience with it myself, though I have heard the learning curve is rather steep... but there's probably a GIMP tutorial community somewhere around.

I'd never have learned about what Photoshop has to offer if I hadn't done a lot of browsing in icon_tutorial, but I do find that these days there aren't many really helpful tutorials posted. So, I thought, let's try something different.