SQL Server 2008 Installation: Sometimes installing a clustered instance of SQL Server 2008 on a Windows Server 2008 Cluster can be difficult to accomplish. Establishing proper permissions for the service accounts and knowing how to perform a slipstream installation can make your installation a success. Make sure that the Windows OS has installed properly (meaning that there were no errors during install) and that the cluster has access to all necessary resources and can fail over quickly. After verifying the Cluster, make sure to disable the User Account Control (UAC) and grant the following permissions to the SQL Server service accounts:
Perform a slipstream installation by following the steps in this KB article:
http://support.microsoft.com/kb/955392
Take note of this KB article to further resolve installation issues with SQL Server 2008 SP1 CU6: