As I mentioned in another comment here, on October 11, the IDPF membership unanimously voted to elevate EPUB 3.0 to a final IDPF Recommended Specification. Apple's iBooks (e.g. on the iPad) already supports some parts of EPUB 3.0 [1], and Kobo says they'll have an e-reader device that supports EPUP 3.0 in the next 3-6 months [2].

[1] http://www.robotmedia.net/2011/08/using-javascript-in-ibooks...

[2] http://www.digitalbookworld.com/2011/five-tablet-trends-sign...