Microsoft has issued a brief announcement that it's releasing a beta of version 8 of Messenger for Mac, which includes A/V support, as promised some time ago.
The software, which interfaces with Windows Live Messenger on Microsoft's main platform, will allow Mac users to join the audio/video party. It's just in beta for now, so you might want to steer clear if you're a little wary of untested software. It's likely it'll get a full release later in the year.
If you do want to try it, though, head on over to Microsoft's Mac downloads page. Oh, and let us know what you think of the beta in the comments box below.