Neowin points to another piece of software that allows you to "convert" protected AACs and WMAs to unprotected MP3s.
Like other programs, they've taken an intersting approach to bypassing DCMA concerns: instead of decrypting the underlying media, they capture the (unprotected) output from the sound card. (In other words, they are technically not bypassing any TPM).
With the DCMA issue effectively avoided, it's pretty reasonable to make a fair use argument here. After all, all we're really doing is format-shifting - and as we saw in Grokster oral arguments the music industry considers this fair use.