In previous versions of Windows, Remote Desktop Services (RDS) was known as Terminal Services. There have been many changes made to this collection of services in Windows 2012. If you are looking for a list of these changes, there are a large number of blog posts out there that explain in detail all the changes.
If you are looking to actually implement the new Windows RDS, there are far fewer resources available. I came across a series of six blog posts today by Shannon Fritz that are excellent and provide nearly everything that a majority of Systems Administrators need to install and implement Windows 2012 RDS. The first link is an overview and provides links to the remaining five posts.