The Network Device Enrollment Service (NDES) whitepaper is now on the TechNet Wiki and I have already made a few updates that were requested. The old download center location has been updated to reflect that we've posted to the update to the TechNet Wiki.
Network Device Enrollment Service (NDES) in Active Directory Certificate Services (AD CS)
Note: Previously the NDES service was called Microsoft Simple Certificate Enrollment Protocol (MS SCEP). You will notice that the Registry and the web interfaces still have that acronym MSCEP.