Though he wouldn't give an exact date, Microsoft CEO Steve Ballmer whittled down the availability window for the company's first big update to Windows Phone 7 at his keynote address to the crowds gathered at Mobile World Congress today. The latest message is that it'll be available in "early March," which puts us precious few weeks away -- more or less on track with what we'd been anticipating -- bringing support for CDMA radios, copy and paste, and performance improvements. Hopefully that clears the way for the 7 Pro on Sprint, eh?