We're very excited to join Nitobi to announce availability of a PhoneGap beta supporting Windows Phone Mango. This new option to build applications targeting Windows Phone gives more choices to developers. In particular, Web developers will be able to easily leverage their HTML5 skills to target Windows Phone.
The beta version of the PhoneGap libraries can be downloaded from: https://github.com/phonegap/phonegap-wp7
This tool makes it really easy for developers to build apps across platforms.