IIRC MusicMoz is running on a special server in the DMOZ server park (the socalled research server), which is currently offline. Since the reason for taking this server offline was not related to MusicMoz and was not related to the server crash, I assume MusicMoz will come back online at some point. I have not seen any ETA though.
6:06 pm on Feb 1, 2007 (gmt 0)
Speaking of which ... MusicMoz is back online. And it seems to be working alright.