NEW YORK ( TheStreet) -- In an arguably make-or-break moment for Microsoft ( MSFT), the software giant launches its Windows Phone 7 operating system today at a launch party in New York City. Way late to a market seemingly saturated with the popularity of Apple ( AAPL) and Google ( GOOG) Android phones, Microsoft's biggest challenge will be trying to set itself apart from the leading duo. At the press event, Microsoft is expected to introduce three phones at AT&T ( T) and one each from HTC, Samsung and LG. Follow TheStreet live as we blog from the showroom floor. --Written by Scott Moritz and Bill McCandless in New York. >To follow them on Twitter, go to http://twitter.com/TheStreet_Tech. >To submit a news tip, send an email to: firstname.lastname@example.org.