[Update: As a lot of people seem to be not reading the documentation and getting stuck with fonts: you need to build the XNA project first, to create the ".exenfont" files the ExEn projects require.]
ExEn is a port of XNA to Silverlight and iOS (and an Android version is in the works). It’s licensed under MS-PL (i.e.: open source) so you can start using it in your games right away, for free! See the included Documentation directory for information on getting started.
As described in earlier posts, ExEn is running behind schedule for various reasons, so this release is missing some features that will be in the final version. The most notable absence in this release is the Android port which, although it is making good progress, is not yet good enough for a public release.
(I tried to get a usable Android port ready in time, but it just didn’t happen. Sorry.)
Now, the lack of Android port here is a bit unfair to people who contributed small amounts (< $50) to the funding of ExEn, expecting to see an Android port today. To remedy that, everyone who contributed – any amount at all, on RocketHub or my own site, up until today – will be given access to the pre-release program (emails go out tomorrow). That way you will have immediate access to features as they are added, as well as the work-in-progress Android port.
For those of you who haven’t contributed to the funding of ExEn, I’m afraid you’ll just have to wait a bit longer. Such is the reality of a software project with a Bus Factor of 1. Sorry. If you like what you see in the preview, you can still join up to the pre-release program.