The Battlefield Blog says an update for the PlayStation 3 edition of Battlefield: Bad Company 2 is undergoing approval at Sony, and they are hopeful this will go live today, also saying they are keeping an eye on Windows and Xbox 360 servers to make sure they keep running. There is also a note on the Bad Company 2 Forums for PC users about PunkBuster issues:

Punkbuster Failed to INIT error

If you see this error and you know who the server admins are then ask them to restart their server. The message is caused by an error on the server side with PB and a restart will clear up the problem.

If you do not know the admin of the server then please find another server to play on.

We are working with Evenbalance to find the cause of this INIT failure and will hopefully get a solution soon.