Since my last entry concerning the mobile video format 3GP, I've come across a much more useful and professional program that converts 3GP to AVI.
It even converts 3GP to animated GIF although the picture quality is obviously greatly reduced and you lose sound in this format.
3GSauron is freeware and is a stand-alone EXE, so you don't have to install it. The only downside with the software I can see is that you can only convert files one-at-a-time.
I've added a link to the authors site below where you can download it.