WinFx Beta Docs and in particular Indigo Community Tech Preview Docs (new) are available on MSDN

I've been asked a number of times when we can expect to see an Indigo CTP Build and I can't imagine it will be off (now there is an informed opinion:-)) but to whet your appetite you can find the CTP docs for Indigo at here.

Also and you've possibly spotted this already but if not then you can find info on WinFX at https://winfx.msdn.microsoft.com and hanging off there on the main menu is a link to Beta Docs and from there you'll find great docs on .NET Framework V2, Indigo, Avalon and WinFX...