[Name] LMMS [Creator] Tobias Doerffel [Linux?] Yes [Windows?] Yes [Note] Free cross-platform alternative to commercial programs like FL Studio®, which allow you to produce music with your computer. Intended as a replacement for Cubase-like software (DAW) [Mac OS X?] 
Yes as of 0.4.0 with Qt4
Y e s
N o
Y e s a s o f 0 . 4 . 0 w i t h Q t 4