Welcome to the Guild Cheesesock! Well there is a lot of information in the tutorials section that will help you take the plunge into digital map making. If you already have Photoshop CS then you'll find that you can do quite a lot with it alone. If not, download GIMP, which, if not as powerful, is hard to beat at the incredibly low price of free. It's a great little program which is well supported in the tutorials here.

Cheers,
-Arsheesh