Microsoft Office 2013 Preview is available for download.
So if you consider yourself the bleeding edge type, you might want to head over to Microsoft today and check out their Office 2013 Preview βeta!
The preview is a Click-To-Run version that can be run alongside your standard 2007/2010 versions. Moshe Silber sent of this Lync 2013 screenshot showing off the new Tabbed Conversation view.
You can grab the bits here @