Does anybody know how to play halo 3 ODST firefight mode over xbox live?

[Owen]

if you know how to please tell me

 

[pie]

Connect to Xbox Live.

Load up Halo 3: ODST.

Go to the Firefight lobby.

Open your friends list.

Invite people you want to play with.

When they join, start game.

If you mean how do you play it with random people, you can't, unless you go to the bungie.net forums and search for people wanting to play it there.