Microsoft reportedly plans to unveil the first Windows Phone 7 smartphones on October 11.
The company will reveal smartphones made by Samsung, LG and HTC and announce an initial exclusive handset partnership with US carrier AT&T, internal sources told the Wall Street Journal.
AT&T plans to start selling the devices the week of November 8, the sources said. But All Things Digital reported that devices would be in stores on October 21, and that Microsoft has signed another exclusive carrier partnership with Orange.
The company on Wednesday launched registration for app developers looking to take part in the advertising program for the new OS. WP7 developer tools and the advertising SDK launched earlier this month.
Microsoft is banking on the OS to stave off the erosion of its market share by competitors such as Apple and Google. Microsoft's share of the smartphone OS market fell nearly halved to 5% in Q2 from 9.6% the year before, according to Gartner.
Its slice of the market is down significantly from the 11.5% share it held around the time of the first iPhone's launch in 2007.