Well, Bungie's servers have been completely overwhelmed... and reports are that you can see the white-hot glow from as far away as Salt Lake City, Utah. However, a couple of mirrors have already appeared for the low resolution 35M version:

• Blue's News
• 3D Gamers - These guys have two servers

We're hearing that the movies, both large and small, should be appearing at FilePlanet soon. If and when they do, the place to look would be here. We'll update you with more mirrors as they appear, and good luck!

Addendum: Bachus has posted a nice synopsis of the movie in the HBO forum. Go and read if it won't spoil the movie for you.