It's winamp.bm8 now, as from 5.58x onwards
(.bm was ansi, .bm8 = unicode)
Though best to save both files, I guess.
WIn7/Vista
C:\Users\(username)\AppData\Roaming\Winamp\winamp.bm8
Win2k/XP
C:\Documents & Settings\(Username)\Application Data\Winamp\winamp.bm8
More info from
FAQ
http://forums.winamp.com/showthread....161361#backup2
http://forums.winamp.com/showthread.php?t=161361#backup