I was using it to debug my brother's machine going through only 1 router (mine). While it was much better than trying to tell him what to do over the phone, it was nasty slow. 10 Mbps plus 300 miles worth of network delays is not fast enough to move a lot of pixel data around. Then I told him to get a router to cut down on viruses and I couldn't get it working again. I didn't spend that much time trying to get it to work (try telling a technophobe how to alter IP settings over the phone), and I haven't gotten around to trying it since.
If your router supports VPN I think it should be easy, but I'm not a network guru. VNC is common enough that I'm sure someone must have put a "recipe" on the net somewhere for how to do this. If you do figure it out, please pass on the info!
Tim