I just got back from visiting my wife's father. While we were there, we set up a new Mac Mini for him. He had been reporting trouble with his 5 year old eMac but I think the trouble was all self-made. So the great thing is, I enabled Remote Access in his computer, made a free account for him at DynDNS.com and installed the free IP updater application. Since most people have a dynamic IP address, DynDNS allows you to assign a name to the computer you want to access. The computer reports its IP address to DynDNS.
This is already saving me so much time. I have spent countless hours on the phone trying to explain how to get the the paper airplane back and other such problems. Now when he calls, I just open my VNC client (Chicken of the VNC) and fix it for him myself.