There's lots of programs that can make GIF files, the commercial ones being Adobe's ImageReady (which comes with photoshop) and Jasc PaintShopPro. If you do a search on google you'll find free ones aswell.
Instead of using animated sprites, what you could do is use a normal sprite, and change the image number it uses whenever you want to change a frame, this means you have to have individual images for each frame though.
Desktop: AMD Athlon XP2800+,Radeon 9800 128MB, 1GB DDR RAM
Laptop: AMD Athlon 64M 3000+,Mobility Radeon 9700 128MB, 512MB DDR RAM