The January Orcas CTP is ready. The new C++ features include .NET Framework Multitargeting (allows the user to target different versions of the .Net framework from a single instance of Visual studio) and Library Versioning (renaming assorted libraries with 9 in their names because they differ from the current versions.) There's a handy list of Orcas features and which CTP they first appear in on MSDN. To view the documents, you'll need an XPS viewer unless you're already using Vista day to day.
Community Technology Previews are not as fully tested as betas, but they're here now, and you can provide feedback after working with them, so why not take a look?