List of Known VNC Flavors

VNC viewer voor PPC en 68k mac
TightVNC
UltraVNC
UltraVNC SC (SingleClick)
MikRFB is a web-based RFB (aka VNC) client. It allows you to control a machine remotely from your web browser. No java plugin required, just a modern web browser.

x2vnc will let you use two screens on two different computers as if they were connected to the same computer. Even if one of the computers runs Windows 95/98/NT and the other one runs X-windows. If they are both running Windows, you probably want to use Win2VNC instead.