The RTM (Release to Manufacturing) version of the Getting Started Guide has been posted to the download center on the Microsoft web site. Currently, the English version of this guide is available. In the next week or two, French, Spanish and German versions of the Getting Started Guide will get published.
The Reviewer's Guide has detailed descriptions about the features and functionality of Windows Home Server.
The final RTM version of the SDK Documentation should get updated later this week on the MSDN site.