Aussie game developer Andrew Russell is developing a cross-platform port of XNA, Microsoft's game development framework for the Xbox 360 and Windows Phone. In a blog entry this week, he announced the availability of the first public preview, which supports Silverlight and iOS. Android compatibility is planned for future versions.

The project, which is called ExEn, was partially funded through RocketHub. The source code is distributed under the MS-PL, Microsoft's permissive open source license. The iOS version relies on MonoTouch, Novell's iOS port of the .NET framework that uses ahead-of-time compilation. It's worth noting that ExEn conforms with Apple's restrictions, which means that ExEn games can be sold in the App Store.

Russell has already successfully used ExEn to produce a port of one of his XNA applications that is sold through the App Store and can also run in a Web browser via Silverlight. To download the ExEn preview and get more details about the project, you can refer to Russell's blog post.