you cant
X-Box live.
Yes, you can.
Yes, Halo Wars is a Xbox Live game, therefore you can play online against other players.
4 players can play through Xbox Live, but only 2 can play on the same Xbox 360 console.
Yes, but only over Xbox LIVE or through system link. You can have up to two people per Xbox if you are playing campaign. The same goes for any Halo game except the first two (you can't play their campaigns over Xbox LIVE, but you can system link)
You can play two players on halo 3 with two controllers
Up to two players can play in the Co-Op Campaign mode on Halo: Combat Evolved.
You can play 4 player co-op on Halo 3, but not all on the same Xbox. To play 4 player co-op on Halo 3 you can either have 4 people all on different xbox's and use xbox live, or have 2 people on each Xbox and either use Xbox live, or System link to join the parties together.
On the Xbox version you can play up to four players in split screen or 16 with system link. Only multi player mode, there is no cooperative play. There is also no online play for the Xbox version. The P.C. version does however support online play.
up to 4 players if u have that many controllers but only on split screen as xbox live stopped
Actually, Halo Reach will allow 4 players to play through the campaign, split screen or through Xbox Live. It's perfectly possible to play with only two or three players as well. As a side note, you can play split screen with your buddy and play with two others on Xbox Live, provided both of you have a Gold Membership.
You and a friend IRL or over XBOX Live work through the Halo : Reach campaign missions