Halo 3 gamer points are points that you get from completing a achievements in the game. This points are seen on your xbox live profile and are for bragging rights.
What you have to do is for the Xbox 360 you have to connect to Xbox Live then you have to get Microsoft points and download the maps but most of the maps are free.
no, you must connect to xbox live to download halo 3 map packs.
You have to have Xbox Live and then go to the marketplace and download them some cost points some dont!
obviously
Yes, you can play firefight in Halo 3 ODST without Xbox live.
Xbox:$200 Halo 3: $50-60 i think Xbox Live:About $80 but you can get it cheaper
Yes, Halo 3 supports multiplayer Xbox Live gaming for any one with an internet connection and a xbox live Gold account
Yes. An Xbox Live Gold Subscription is required to play Halo 3's multiplayer.
You have to download it over xbox live
get an xbox live gold account, connect to the net, and play.
Yes, you have to pay for Xbox Live for any game