Found this brilliant free music file convertor.I wanted to change my wma files all to mp3 files and it did it easily and quickly.theres a few more other files it converts either way.wav, ogg etc. Go to www.download.com and type in "Switch 1.05" ( without inverted commas) It's a very small download, and so easy to use.Theres no adware/spyware, as I have checked with Webroot Spysweeper and Trend Micro.
Good Luck