I recently downloaded a program that will convert .flv files to .wmv or .mpg or .avi format. It is called SUPER by eRightSoft, and it will convert different types of files into other formats. I tried this utility by converting an .flv file from YouTube to an .mpg and while it ended up being a larger size than the .flv after conversion, there was no significant loss of video quality from the original. The best part about this....its FREEWARE!!!!
You can go to the company's website to get this tool. Granted it is a 25MB download for the install program, but I think it is useful. Get it from here:
http://www.erightsoft.com/home.html