Beta key with preorder

Reserve StarCraft II: Wings of Liberty and receive an invitation to the StarCraft II: Wings of Liberty beta. Available online and in-store while supplies last. Once you receive your Beta Code your order cannot be canceled. Online Customers (web delivery): A code and instructions on how to join the beta will be emailed within 1 business day of when your order was placed. In-Store Pickup Customers: Please wait 24 hours after your order is placed, then proceed to your store to pick up your beta code. Store Customers: A beta code will be printed on your pre-order receipt.

I wonder how many 'supplies' they have? Beta keys were selling in the hundreds on Ebay, i'm sure these will go fast. Good find though. Are you planning on pre-ordering it?