The package included an authorization code to download a Digital Copy from the Warner Bros. Internet site. Cut&paste from the WB support information FAQ:
What is a Digital Copy? Digital Copy is a Windows Media™ compatible copy of a movie which can be quickly and legally transferred from a purchased DVD to a PC or PlaysForSure™ portable media device.
How do I get started? To use Digital Copy, you will need a PC running Windows XP or Windows Vista, Windows Media Player 10 or above, a DVD-ROM drive, and an Internet connection. No downloading is required but you'll need to connect to the Internet the first time you run the disc to enter a special code to get your copy of the movie.
So I downloaded the Digital Copy of "The Dark Knight" in a couple of hours: there are two separate Windows Media files. The first one is 2 GB, 720x400 at 25 fps format with an average bit-rate of 4.5 Mb/s and includes five languages: English, French, Spanish, German and Italian. The second one is 625 MB, 320x176 at 25 fps format with an average bit-rate of 600 kb/s and includes only one language (Italian, in my case). The quality looks good, but nothing comparable to Blu-Ray, of course.
Oh, and by the way, be very careful with your authorization code:
How many times can my authorization code be used? The authorization code can be used once. One authorization code will provide 1 PC and 1 portable media device copy license.