Creating a Test AD on an existing network

Hello,

I currently have a Primary Domain Controller with Active Directory running on Windows Server 2008.  I would like to create a test AD server on the same network which testers and developers can RDP to and point there LDAP connections to to test programs with.  For the obvious reason, this is needed so the testers and developers do not query or change setting on the main PDC's AD.

What is the best way to go about this?  

Thanks,

Jason