A new plug-in you will find within the ‘explore’ under the Online Media.

A partnership with Microsoft to bring CinemaNow content to Windows Media Center. That means you can browser and purchase or rent videos using a remote control and a 10 foot interface. CinemaNow has over 3400 feature films, 3000 TV episodes, and 2900 music videos in its library.

http://www.tvsquad.com/2008/05/22/cinemanow-movies-now-available-in-windows-media-center/