Remember that agreement between Microsoft and Yahoo! to make their clients interoperable? It’s happening. Currently, Y! Mac messenger will work with Windows Live Messenger
So all of you guys who are waiting to get your yahoo mail beta invites, here’s a simple trick, it should take you a minute and you will get the new beta interface!!! Enjoy 
Yahoo introduced on Monday a beta of its Yahoo Messenger with Voice chat application that includes free plug-ins designed to let people to do things like track eBay auctions, see friends’ wish lists on Amazon.com, collaborate real-time on event planning and compare calendars with contacts.