not sure if it works. but you can try this...
http://www.programurl.com/rm-converter.htm
btw. just thought of another way wizeone. You'll have to let the movie play it's full length and have a lot of harddrive space probably. but you can use fraps. it can capture any programs output pretty much )
check the admins-only download section on peq for the fraps download wize, i bought it the other day )