[X4U] Applescript or terminal gurus: how to force video mirroring?

[Michael Elliott]

I access my home machine from work via Chicken of the VNC plus the  
Mac's built-in VNC server.  The speed has never been what VNC was  
under OS 9 <sigh>.  But now that I've added a 19" monitor in desktop  
spanning to my new 20" Core Duo iMac, the screen refresh is  
staggeringly slow due to the overhead of the new monitor.

I'm completely unfamiliar with remoting (is this what everyone refers  
to as "SSHing") from another machine.  But I was wondering if an  
Applescript guru would know a script to switch the remote Mac back  
and forth from screen spanning to screen mirroring?  I could launch  
the script remotely (or just wait for the screen to finish drawing  
all the way in VNC...) and then launch the script, thereby at least  
reducing the size the "screen" that VNC has to transmit and refresh.

Thanks!

Michael