Good and bad news out of Comic-Con 2012 this evening. Joss Whedon has revealed that his cult favorite webseries Doctor Horrible's Sing-Along Blog is coming to The CW next year. What's the bad news? Well, he may just be airing the old webseries on broadcast TV instead of producing new episodes.
Star Neil Patrick Harris is committed to his CBS series How I Met Your Mother, so its unclear if he will be involved should new episodes be produced. It is not known when Doctor Horrible's Sing-Along Blog will premiere on The CW, but it is possible that it could be a limited-run summer series that would include Neil Patrick Harris. This is all speculation at this time, of coure.
The original Doctor Horrible's Sing-Along Blog consisted of three acts, or episodes if you will, and premiered to much fanfare in 2008. Joss Whedon wrote and directed the "mini-series" with his two brothers Zack Whedon and Jed Whedon, and his wife Maurissa Tancharoen.
One extra thing to note, even if new episodes are produced for The CW, that does not rule out a feature film sometime in the near future.