From the EA Battlefield Blog:
BFBC2 PC on Steam For Pre-Order
Last week we finally released BFBC2 PC on Steam for pre-order. It was met with an overwhelmingly positive response and in just two days of being available rose to the #2 slot in sales last week and currently #1 for this week on Steam. So a HUGE "THANK YOU" to the Steam Community for the warm welcome and joining us in the Beta through your pre-order and a special "you rock" from our Executive Producer KM (L_Twin).
For those interested in pre-ordering BFBC2 PC on Steam can click here.
BFBC2 PC Beta on Steam
The Beta will appear in your "My Games" tab in your Steam client to all Steam pre-orders for day one access to the Beta.
Look for another blog later today with even more details on the Beta! :-D
From what I've read elsewhere, beta keys will go out the 28th, with the beta starting the 29th. Post here if you receive yours!