VMO will not run on the Mac OS, however voice mail messages will appear at email with attached WAV files on a Mac Outlook client and you can play the messages fine.
If you change your audio compression to anything other than the default MuLaw format, you might run into trouble, however. There is no codec available for the ADPCM formats for the Mac. As long as you stick with the installed defaults (which can only be changed by editing the registry) you'll be fine.
Jeff Lindborg
Unity Product Architect
Active Voice Corp
jlindborg@activevoice.com