Looks like Halo 3 is still coming despite MS denials today its been spotted first in the Steam registry (along with AOE 2 HD which is now announced) & now its turned up in the latest 13.3 AMD drivers
so why would those 2 unreleated companies list the same Halo3.exe file twice 
http://www.eurogamer.net/articles/2...-halo-game-on-steam-or-a-pc-version-of-halo-3


http://www.eurogamer.net/articles/2...-halo-game-on-steam-or-a-pc-version-of-halo-3