Ive never herd of MAD but I use a program called dBPowerAmp that converts WMA/WAV to MP3's and vice versa and i think you get a good result.You can get a free 30 day trial here....(But you might be able to get it on a P2P site if you now what I mean )

http://www.dbpoweramp.com/dmc.htm

All so there is a WMA codec for it here..

http://www.dbpoweramp.com/codec-central-wma.htm