Well, everything apart from the fact that it will be released sometime in 2010 and that is a FPS set the the Halo Universe, is speculation. For all we know it will be Flip Yap telling Yap Flip about how he participated in The Battle of Reach while they're eating Mud Wasps on Balaho.
Bungie will be Bungie and will release information when they feel like it.
~Hunter
[Edited on 06.28.2009 12:15 PM PDT]