Welcome to the Guild Lin. I agree with Viking that the tutorials section is your best bet to begin with. If you don't already have mapping software, Photoshop CS and GIMP are probably the two most popular used around here. Once you find a tutorial that you like, start a WIP showing your progress. Others will chime in an offer helpful tips and pointers that will help you along. Looking forward to seeing you around.

Cheers,
-Arsheesh