It appears that Microsoft is working on, or at least considering, to launch a Zune Phone.
The evidence for this is a patent application which was filed on June 16th last year for a user interface of a smartphone:
Microsoft's patent application -- filed June 16th of last year -- is for a dynamic tiled interface for "improved user interface for mobile devices such as smartphones" and "personal digital assistants." The pic shows pretty much all the things you would expect on a PDA (but where is the dialer icon?) including music, weather tools, browser, flying saucer control (or is that a ship?), and, of course, a doggy. We kinda dig the concept of a tiled interface -- and who knows, if true, this may just give the Zune a better whack at the oncoming iPhone behemoth.