GIMP is a great software program for digital image-processing. The example below was made entirely using GIMP (I didn't make it). This program is great for making skins and other moding stuff in TT. You can use it in many other things too such as in websites. Go to downloads at the GIMP web site to download it. This program is avalible for Windows, Mac, and Linux.

If you want to get stuff for websites or banners (sigs even) you can go to flamingtext.com and make them. It generates the images using GIMP.