"Stealth" VNC

[James M. Henderson]

Hello List
 
I am a school network admin, & I need to be able to monitor student's activities without their knowledge.  (Just call me Big Brother)  
 
The idea is that, during classes when no supervisor is physically present, there is still some supervision across the wire.  However, some students have now twigged to the fact that when the VNC tray icon turns dark, they are being monitored.  When this happens, they immediately switch tasks, until the icon shows that the supervisor has moved on.  They then return to whatever illicit task their creative little minds desire.
 
Can someone point me to a "stealth" version of VNC that either shows no systray icon, or where the icon does not change ?
 
Thanx
 
Mick Henderson
jhenderson@bne.catholic.edu.au