There is an article over at Bungie.net introducing the H2 Vista development team.
"It’s about time we introduced Bungie.net to the crew working on Halo 2 for Windows Vista. The hard work is being done by a team within Microsoft Game Studios, codenamed Hired Gun. H2V is their first project together, but the group is staffed by old hands in the gaming business.
Bungie's role in this project is mostly advisory, but we shouldn't donwplay the importance of that. We’re helping with design decisions and making sure that Hired Gun has access to Bungie artists and designers when they need a second opinion. In all other respects, the folks listed here hold the reins to one of our favorite horses."