.Here's the best place you can go: www.zamzar.com. Go there and you will see it's very easy to use. They will convert your video, and then send you a link in email from where you can download the converted video.

Or, there's a software you can download for free called "AVI MPEG WMV RM to MP3 Converter". Go to google and search for it. I always use that one. Very reliable and no compromise on video quality.