This new update revamps the AppleTV Interface and allows you to rent movies for direct playback on your TV.
Movies rentals cost $3.99 for New Releases and $2.99 for older titles. Hi-def movies can be rented for an additional dollar. You have 30 days from the time of purchase to start the movie. Once started you have 24 hours to complete watching the movie.
You can find the tour of iTunes Movie Rentals on the AppleTV: here