Information below was found on another site - I hope it's accurate. If Amazon wants to add this to the description and delete this comment it's fine with me.

Single-Disc Edition:

* 16×9 widescreen version of the film or 4×3 fullscreen version of the film
* English Dolby Digital 5.1 EX Surround Sound
* English & Spanish subtitles
* Closed captions

Two-Disc "Shake and Shimmy" Edition:

* "Behind the Beat" picture-in-picture option allowing viewers to watch behind-the-scenes footage and on-screen commentary concurrently with the running feature (HD Exclusive)
* All new musical number, "I Can Wait"
* Feature-length audio commentary from director and choreographer Adam Shankman, star Nikki Blonsky and producers Craig Zadan and Neil Meron
* Deleted scenes with audio commentary from director and choreographer Adam Shankman and star Nikki Blonsky
* "You Can't Stop the Beat: The Long Journey of Hairspray" documentary
* "Step By Step: The Dances of Hairspray" featurette offering how-to dance instruction
* "Hairspray Extensions" featurette, giving viewers dance breakdowns
* Jump to a song with optional sing-along feature
* "The Roots of Hairspray" featurette
* Interactive menus
* Theatrical trailer
* 16×9 widescreen version of the film
* English 2.0 Stereo Surround
* English Dolby Digital 5.1 EX (on feature, deleted scenes and interactive menus)
* English & Spanish subtitles
* Closed captions