On April 15, 2010, it has been announced that Microsoft will discontinue the Xbox Live for the original games for the original Xbox and the Xbox 360. What this means is that you can still play the original Xbox games in single player or offline mode, but can’t play them online.
With this announcement, Microsoft is giving Halo 2 fans a reward for getting rid of online portion. They will receive a free three month Xbox Live membership, accompanied by 400 MS points and a chance to play the Halo: Reach beta.
Source: Xbox.com