Wired News has a good article giving general information on the SP gameplay and a pretty good smack on the MP gameplay.

“The single-player campaign for Halo 2 is like an air horn on its last gasp: It starts out bold and brassy but ends in a sad little squeak. The online component of Halo 2 is like an exclusive restaurant: It takes a while to get in, and you dont have as much say in the menu as you might like, but the results are good enough that you dont care.”

Read the full article here: http://www.wired.com/news/digiwood/0,1412,65732,00.html