Check out the acknowledgements on my help page for links to the free graphics programs that I used for the gifs on my website.
Xara Webstyle really helps you to be creative. Irfan View is the very useful for resizing scans to a precise pixel count, and for making interlaced images. Recently, I have started using Serif Page Plus, which also produces some fine gifs with drop shadows and transparency. I never noticed any problems with graininess - have look at the graphics on my site.