microfab - what server are you using? I am using TightVNC and can confirm it works here. What "Screen" or "Desktop" number did you set on the desktop? I believe if it is not 0 you need to use IPADDY:# on the client... Are you on the same LAN? If not, that will be your problem - need to have your router port forward the propper port(s) to the host pc's internal adress - 5900 is for desktop 0, 5901 for #1, etc...... If you are on the LAN, make sure you are using the internal IP's (Unless port forward is set up). If you are NOT on the lan and you do have port forward setup, make sure you are using the EXTERNAL ip, which is probably NOT the one in the desk bar -- you can find it somewhere in your routers config pages - you can also setup a DDNS type service to point back to that external ip from the net.......

if you already tried all that, sorry I am out of ideas.... -

Hope this Helps,
Patrick