The Battlefield Blog announces plans to add a co-op Onslaught gameplay mode to Battlefield: Bad Company 2, offering a trailer showing off the mode. The update only mentions this coming to the Xbox 360 and PlayStation 3, which has inspired numerous comments from perturbed PC players. The question of whether this is coming to the PC is addressed in this post by DICE Associate Producer Barrie "Bazajaytee" Tingle, who indicates that they may yet bring Onslaught to PCs, but they are struggling with how this would impact dedicated servers. Word is:

The question of "What about PC?" is coming up in the comments quite a lot already so this is what the situation is.

No, we haven't signed away rights to console on this. The problem we have on PC is that all our servers are dedicated with providers. Changing a server from Conquest 32 players to Onslaught 4 players cuts out 28 player slots from the total ammount available. This could have a dramatic affect on the PC online environment if enough servers changed to Onslaught.

We aren't ruling out Onslaught on PC but at this time we are researching how to bring it to PC without affecting players who don't have Onslaught or their own server to run it on.