Well, both Yahoo & MSN partenerd recently and added the ability for adding @hotmail and @msn users to your Yahoo Pal List -- And @yahoo folk to Messenger Mac's list -- so that's a step in the right direction.
I'd be curious to know if - on the PC side - if a PC webcam MSN user can share video with a camera-enabled Mac Yahoo user. Does 'View My Webcam' show up? It'd be a good thing to test and possibly add to my
http://www.mac-compatible-web-cam.com site FAQ.
Thought I'd read a rumor that the Mac Business Unit - once Office 2008 was finally shipped - would be releasing a much improved (read video-enabled) Mac Messenger later this year...