VLC Media Player is one of the most downloaded and used media players out there. Free to use, and has one of the largest codec databases for virtually all multimedia either downloaded from the internet, or just for playing your DVDs. Just about everyone recognizes the yellow and white cone associated with VLC...more..
Update 3/1/10 Gom Player, which I now use, is now the number one free media player.
With this easy to use program you can convert your WMA music to mp3. Also supports wav. and ogg file conversion.
I use this a lot. It is great for pesky windows media files that won't play on some hand held devices or burn to disc in a playable format.
Just add your tunes, click and convert!
CyberPower