Transparent Gif Makers
Too many times new dollists are stuck with the dilemma of the "transparent gif" rule. Most contests insist your dolls are transparent and only a handful will actually make them transparent themselves. It's a pain. You cannot upload BMPs, most free server will just convert and compress it anyway, so what you're left with is to either make a JPEG or save it as a GIF in paint, and we know what kinda disaster that can be. Observe:
See? If you GIF it in MSP it dithers all ugly-like, and if you make it a JPEG.. well.. ew? It's messy, it ruins your coloring job, and most contests just won't take it. Listed below are GIF-making programs and sites available for you to use (If you have any suggestions, please drop me an email):
GIFWorks.com 
This site was fairly useful in my early days of dolling and is pretty helpful. i am not sure if they do animated gifs. They probably do not. The method is simple. Upload a picture, choose the transparent background. GIF it. They provide instructions.
Gif Construction Set Professional 
Before i got GraphicsGALE, i used this to make my transparent gifs. It's got a free trial and when the trial runs out it gives you a nag notice for 20 seconds then you can continue to use it from then on. It's annoying though 'cause the nag notice shows up every time you open the program. But hey, cheap as free right? To make a transparent gif (and not animate it) you upload the BMPs, delete all but one frame, double-click the frame, click the transparency checkbox and choose the transparent color. Save. WARNING: Animated transparent gifs with any movement outside of the picture will leave a trail with this program. Pain in the ass.
Animated Gif Maker
I never used this before. I only found it when I googled for it. I imagine it's a system very much like Gif Construction Set Pro in that you upload a bunch of BMPs, pick the transparent color, then save it as a gif.
GraphicsGALE 
There is a free trial and it is the best animator on the market. It's also good as a replacement for paint. It has layers and all kinds of goodies. Problem is with the trial you cannot save as anything but a BMP. Bummer.
IAZA
Suggested by Natalie (no site available). "another good gif-transparency site is www.iaza.com i use it SOOOOO much"