.Net 3.5 Enhancement Training Kit has been released to the market on 11th April. In fact I rather call it ASP.Net & ADO.Net 3.5 Enhancement as the contents are ASP.Net and ADO.Net related.
The current version of the training kit only includes Hands-on-lab. The presentation, demos, screencasts and resoureces are not available that. But I think HOL is a good way to start with.
Jonathan Carter , Technical Evangelist from Microsoft wrote a informative blog about this training kit.