The third and final Act of* Doctor Horrible's Sing-Along Blog* goes posty today. All three acts can be seen at drhorrible.com until Midnight on Sunday, July 20th. After that, they can be only found (legally, anyway) in the Televsion Section of the iTunes Store for $1.99 per episode, or $3.99 for the Seasons Pass.
Doctor Horrible was created during the Hollywood Writer's Strike by Joss Whedon, his brother Zack, his half-brother Jed, and actress Maurissa Tancharoen. The reason it was created is best described by Joss in the Master Plan he posted on the Interwebs:
Whedon put up the money to create this project himself. He is expected to announce at Comic Con details on the release of a full-length Doctor Horrible DVD, which will purportedly contain lots of extras, including a rumored sing-along commentary track. He is hoping to pay the cast and crew from the proceeds of iTunes and DVD sales.