Very cool technology I came across at http://www.lifehacker.com/
It's called quickscreenshare
It's a tool for sharing what you're seeing on screen, or remotely managing someone else's PC to help them out.
It generates a one-use link that you must email to the person you're working with (or if you're insane, dictate the soup of characters that comprise the URL).
It also seems to be secure: either party can end the session, and reconnection requires generating a new link and an acceptance on both ends.
At the moment it's free, and seems to be a bit more responsive than the otherwise excellent
tool, Fog Creek Copilot http://www.copilot.com/