Apple, regarding the distribution of iTunes LP and iTunes Extras:
Automatic, electronic submission of your iTunes LP or Extra is scheduled for the first quarter of 2010. Until then, the submission process is manual and limited. Please contact your label or studio rep for details and consideration. An existing iTunes contract is required. Your iTunes LP or iTunes Extras will be reviewed by the iTunes team for appropriateness of content and for technical quality.
This has the potential to become another App Store. But, since there is no copy protection on iTunes LP and Extras, content creators should be able to release their Extras and LPs on the web, bypassing Apple and iTunes entirely.
Update 12/8/09: The Boy Genius Report cites a source of theirs that claims that iDVD will be gaining iTunes LP creation support in an upcoming release (most likely with the new iLife suite). With DVDs becoming less and less relevant — this makes a lot of sense, however I would expect that (if true) Apple would change the name of iDVVD with this release.