The new phones, from handset makers including Samsung (SSNHY), LG (LGLD) and HTC (HTCXF), will be available with AT&T (T) coverage starting next month, Reuters reported.
Microsoft, the world's largest software maker, has just 5% of the smartphone market, compared with 17% for Google's (GOOG) Android platform.
Worldwide sales of smartphones will rise 56% in 2010, according to research company Gartner. Sales of personal computers are expected to rise 19%.
Earlier this year, Microsoft pulled its Kin phone less than three months after the launch. The Kin was aimed at teenagers.