Infinity Ward has said that Modern Warfare 2 multiplayer supports third-person view in private matches.
"You obviously will still have the option to play gametypes normal as well," he added.
Private matches supporting third-person mode will be labelled as such in-game, so you should have no trouble working it all out.
Modern Warfare 2 is due out for PC, PS3 and Xbox 360 on 10th November. Check out our recent hands-on to see what we make of it.