2 Disc Special Edition of Serenity..

will be coming out this Summer.. Joss confirms it and some of it's features here.

My favorite snippet in reference to comments about Joss going "all George Lucas" at then end of his post:

Take my Yub,
Take Yub Yub,
Yub Yub tak the Yub from Meee...dichlorians.. -Joss