PhoneGap 1.3 has just been released and now offers full support for Windows Phone 7.5.
You can read details about the release on the interoperability @ Microsoft blog.
In order to see how this works, you can watch the videos below. The first one is an introduction, while the second one is a more detailed “Getting started” guide.
To download the framework and the Visual Studio templates, visit the PhoneGap.com site.