Surface technical resources are now public. You can find on the official Web Site:

The Surface SDK (http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=3db8987b-47c8-46ca-aafb-9c3b36f43bcc) The documentation Tools and resources User experience guidelines Microsoft Surface core applications (http://www.microsoft.com/surface/Pages/product/applications.aspx )

The official Web Site: http://www.microsoft.com/surface/Pages/Technical/Learn.aspx