Actually there are two type of activation methods for Microsoft office 2010, using multiple activation keys(MAK) and using key management service(KMS). Multiple Activation Key (MAK) is used to activate fewer than 50 computers. Key Management Service (KMS) for activate thousands computer at the same time. On this Post I only provided Multiple Activation Key.
You can activate your Microsoft Office 2010 beta by entering your product key. You can use one of the 3 options to enter the product key. For more info how to activate Microsoft Office 2010 using your product key you can open this website.