The app from Sanus includes the MountFinder and HeightFinder tools from Sanus, which do pretty much what you'd expect.  The MountFinder helps find compatible mounts for over 15,000 different TVs and the HeightFinder helps you find the exact place to drill that first hole.

The app also includes a few videos displaying the different types of mounts available and the advantages of mounting a television.  The Sanus Install Tool Kit is available now as a free download.