There are now a number of sites offering online movie downloads and even rentals. If you’re using a Mac, your only choice is iTunes but Windows users have a few options. TechCrunch has posted a small review of such sites, comparing CinemaNow, Movielink, Guba, Amazon Unbox and iTunes. DRM plays a big role in what software and options you will have and the review does a good job of highlighting these.
Source: Digital Media Thoughts