Brannen Boren (of Boren's Syndrome fame) updated his blog on Saturday and included a note about Halo 2:

Looking forward to the release of Halo 2. As the "Keeper of the Halo Story Bible," I reviewed the Halo 2 script for continuity and setting sensibility, and submitted a list of suggestions before I left Microsoft, but I didn't get to stick around long enough to see whether they acted on those suggestions. I played the multiplayer for Halo 2 some time ago, but I'm looking forward to seeing how the story for the campaign differs from the original script I read.

Original script? Wonder if that will ever be published...