The Best VNC Software
I really like VNC, It helps me in my every day work. Most of the time I wanna share screen to see my Colleagues screen and help them out or vice versa.
There are different VNC software which you can use, for example, TightVNC , RealVNC and UltraVNC. So lets see which one is the best.
tightvnc
I didn’t use this one very much, because of the other ones 
but it seems quite cool software beside its Open Source and free. But it has ~ like many other remote screen software, problem with multiple monitors.
RealVNC
I used this one for quite long time and I really enjoyed using it But you gotta purchase it.
It has also free version but free-version is featureless and has nothing compared to other free VNC software.
Like TightVNC it has problem with multiple monitors.
UltaVNC
Now I use this guy. I think its The best one. First of all its Open Source and free and the other one it doesn’t have any problem with multiple monitors.
UltvaVNC has cool Addons, you may like to check them out here.
One of them is called singleclick. Its awesome , you can create a single file and send it to your customer, this file is just 166k. When they click on it and run it you can connect to their computer remotely. Its better than Remote Assistance or any other solutions
VNC Software in other environments
PortableVNC ~ PSP
There is a application called portablevnc, Its vnc viewer for psp
PalmVNC ~ Palm
Its vnc viewer for Palm OS® platform.
SymVNC - Symbian
Its VNC viewer for Symbian 3rd Edition .
J2ME VNC ~ J2me
Its VNC viewer that uses j2me api. Theoretically it must run on every smart phones.
JaaduVNC ~ iPhone
Its VNC viewer for iphone