I feel that as a Buffy fan, Browncoat, and general lover of all things Whedony, it is my duty to pimp this as much as possible.
1. Go HERE to find out WTF this is all about.
2. Here's the OFFICIAL WEBSITE.
3. Yes that is, in fact Neil Patrick Harris (aka Doogie Howser).
Teaser from Dr. Horrible's Sing-Along Blog on Vimeo.