Microsoft has released Windows Server 2008 RC0 Datacenter

This time-limited release of Windows Server 2008 Release Candidate will expire on April 7, 2008. After this time, you will need to uninstall the software or upgrade to a later release or a fully-licensed version of Windows Server 2008.

This product requires a valid product key for activation you may install the product without activation, but if you do not enter a valid product key and activate within 30 days of installation, the software will cease to function.

If you have received a product key via email confirmation, you may use the key with the software you download from this site or with a DVD containing Windows Server; 2008 Release Candidate.

Windows Server 2008 RC0 Datacenter