OK I'm not sure if this is the right forum, I couldn't find a better area to put this in though

How do I convert .3gp files to .avi or .wma files? (Or .mpeg) I've got the Nokia Multimedia Converter but that converts the other way, I have loads of movies on my phone that I want on my PC. So how do I make them viewable through a player such as Windows Media Player or WinAmp??