When I set up my testserver I only had one disk available. Afte a while it started filling up, so I added a second disk to it. To move the RemoteInstall folder from the Windows Deployment Services in 2008 while keeping all the settings I followed this procedure:
Using elevated privileges Start –> Run –> cmd
Run WDSUTIL /uninitialize-server
The copy the RemoteInstall folder to the new location (in my case D:\)
Run WDSUTIL /Initialize-Server /RemInst:D:\RemoteInstall
Your WDS storage is now moved to the new location. Needless to say, but you should now check to see that your still able to PXE boot and install images.