VNC fun on Mac OS X Server. Info from Apple.
Enable VNC access (on test machine)

Go to your admin computer, or a client computer, that either has VNC access enabled or it can be enabled.
From the Apple menu, choose System Preferences.
Click Sharing.
Select the Apple Remote Desktop service (by clicking its name, not necessarily its checkbox).
Click Access Privileges.
In the resulting dialog, select the "VNC viewers may control screen with password" checkbox.
Enter a VNC password in the field to the right. The password you enter will be the password you assign to other clients later.
Click OK.