>Am checking out Ultra VNC SC... etc.
>Does anyone use such a software?

I've used Ultra VNC for a few years, and just started using Single Click recently. Single Click is great for computers where it isn't possible to install software, or where I hadn't planned on connecting to. I just email the zipped exe to the client, they open it, click on "connect", then we have joint control of their computer. Much easier than walking them through an install of the VNC server. Arg.

One downside of single click is that you either need a known static IP at your workstation for the users to call back to. This requires you to upload the IP to UltraVNC's site. So you may have to have several version of the single click call back app if you are at different locations when you support people.