The PC version's servers can hold a maximum of 64 players, while the Xbox 360 can hold up to 8 players.
Most of the maps featured in multiplayer are set in either France, Germany, Russia or Libya, although some are set in other North African countries. As in the campaign missions, you can choose to play as a Russian, British or American soldier if you are on the Allied team; if you're going Axis, the Germans is the only choice.
Unlike the campaign missions and the multiplayer mode of Call of Duty: United Offensive, you cannot use vehicles in any way.
Being more of a campaign based game, most of the multiplayer modes in Call of Duty 2 can also be found in the original Call of Duty. In addition, many more detailed multiplayer modes can be found on Call of Duty 3.