Spring RTS Engine

GIMP
http://www.gimp.org/
Just save as .gif
Gimp will ask you if you want your image-layers to become animation frames.

simple to use tools i use all the time:
http://www.whitsoftdev.com/unfreez/
for making several still .gifs into one animated .gif

http://www.virtualdub.org
for making videos into .gif, use decrease framerate etc. for smaller file size.



weeeeee