I would start by first
think of it as upgrading any componnet inside the ePO server
1. make sure you disable all your protections on the ePO server if its the same as the DB server if you have it
2. Get some of the requirements mentioned on this link
.3. I would say use adaptive policy or learning policy for the applications and firewall to make sure that you dont have an issue then push what you find in to a policy master policy
You can install SQL Server 2008 Standard as an additional instance (apart from the SQL Express instance which is hosting the ePO database). Then its a matter of using SQL Server Management studio to connect to the Express instance, backup the ePO database and restore the backup copy to the new SQL Server 2008 instance. Finally, point ePO to use the SQL Server 2008 instance (http://localhost:8443/core/config).
There are several KBs in the McAfee Knowledge base which describe the steps to backup and restore the ePO database.
Hope that helps.