We just posted the second developer preview; this will be our last release without screens. The big new feature is the report engine, but we’ve added or changed numerous other items. We also included source code for a few of the modules, as well as partial API documentation for the entire framework.
If you're in the Beta group, you can download the release here. If you aren't in the Beta group but would like to be, contact me. As with the first developer preview, don't download this unless you are an intermediate to advanced Microsoft dot Net developer.