I’ve been wondering why there aren’t more free internet remote support solutions given that there is very good open source code out there to accomplish this (i.e. VNC).  Using VNC requires knowing the host IP and having TCP 5900 open through whatever firewalls the host is using.  I have come across a couple of free solutions on TechRepublic that might serve this purpose:

crossloop.com

teamviewer.com

I like Crossloop – built on VNC and offering a whole support community  sort of thing.  I have only tried it over a shockingly slow connection to Africa though and it was pretty painful..