EA said today that Bad Company 2 is to get a four-player co-op mode named "Onslaught".
The mode can be played with up to four players across four multiplayer maps – Valparaiso, Atacama Desert, Isla Inocentes, and Nelson Bay – redesigned with new lighting, time of day, added vehicles and other stuff.
Each map has a dedicated gameplay focus. The update's "coming soon," apparently.
There's only mention of Onslaught for 360 and PS3 in this press release. Nothing for PC. There's no mention of cost there, either.