http://www.microsoft.com/downloads/details.aspx?familyid=F0C9DAF3-4C54-45ED-9BDE-7B4D83A8F26F&displaylang=en
The Microsoft SharePoint 2010 (Beta) software development kit (SDK) contains conceptual overviews, programming tasks, samples, and references to guide you in developing solutions based on SharePoint 2010 products and technologies.
