Indigo CTP is out there! Well, at least for the MSDN subscribers. Go grab the bits from http://msdn.microsoft.com/subscriptions/default.aspx. If you also want documentation and samples, you'll need the WinFX SDK - http://winfx.msdn.microsoft.com/ as well.
Go play with your new toys and don't forget to tell us what you do like, what you don't like and what plain sucks.