Buckets.
![](http://img247.imageshack.us/img247/3623/sig1lp2.png)
http://panda.whahay.net/ConvertShots.exe
Not exactly entirely automated, but you put it in your screenshots directory, and just have to run it for it to convert all the files in the folder from TGA to GIF. I don't know what rami made, but I imagine it's pretty similar.