I've got a bunch of headless G5 Xserves and originally I had to run OSXvnc, it's not too bad. We then bought a copy of ARD to use and after upgrading the ARD servers to version 3 the VNC problems went away so we removed OSXvnc and just used ordinary ARD/VNC. One word of warning though, I've found the VNC server to be rather flakey requiring a login over ssh to manually restart the process.