In a Tuesday announcement, Microsoft and its partners said that the much-awaited first set of phones carrying the updated Microsoft's mobile operating system, Windows Mobile 6.5, is all set to hit the stores.

The first three Widows Mobile 6.5-based phones include Verizon's HTC Imagio and AT&T's HTC Pure, and HTC Tilt 2.

Microsoft expects over 30 phones running its new Mobile OS by the end of this year, with a number of them debuting from now onwards till the holiday season. Moreover, as per Microsoft's February announcement of the Windows Mobile 6.5, some current Windows Mobile 6.1 phones can also be upgraded to the new Mobile OS.

While the updated Windows Mobile 6.5 is largely a reinforcement of Microsoft's conventional OS, it boasts an additional app store and a few usability enhancements. In addition, the operating system also features an improved browser, Adobe Flash support, and easy-to-navigate menus.

With Windows Mobile having faced a downslide in its market share, with fierce competition for RIM and Apple, analyst Tina Teng at market researcher iSuppli said: "Windows Mobile is facing a host of challenges, including rising competition from free alternatives like Symbian and Android, the loss of some key licensees, and some shortcomings in its user interface."

However, Teng also added that "Windows Mobile holds some major cards that will allow it to remain a competitive player in the market."