The operating system for mobile devices is key to Microsoft's push to win market share from Apple's iPhone and Google's Android software.
Microsoft chief Steve Ballmer is expected to do the unveiling and to confirm that the first devices to run the software will be available before the end of 2010, according to the Financial Times.
The unveiling is expected to concentrate heavily on the user interface of the latest version of Windows Mobile as Microsoft seeks to win back users who have turned to its rivals.
Microsoft's share of smartphone software fell 18% in the US in the final quarter of 2009, while Apple's iPhone grew 25%, according to comScore.
Apple's iPhone user interface has challenged all smartphone producers and Microsoft will have to focus heavily on this area if it is to remain competitive, according to analysts.