At long last we are hearing some more on the Yahoo and MSN interoperability deal that was announced last year, thanks to Leah over at the team blog. The interoperability will allow users on both services to send basic IM's to one another, and see each other's status. I suspect that some users will be disappointed by this, but as it's taken two companies this long to get here, lets be grateful for whatever they provide us.
I know the first question that testers will be asking is "when can we try this?" I would not expect beta testers (both managed or those on ideas.live.com) to get a test build before Messenger goes final, though as always, this could change. So now the second question will be "When is it going final?"