webex or gotomypc equivalent service

[Keith Morse]

I'm wondering if any list members have heard of a OSS project that
replicates this functionality?  I've been doing a good deal of free tech
support with relatives and friends on their their MS Windows based
pc's.  It would be nice if I could gain access to their desktop rather
than having them verbally relay what they see.

I'd have control of a server acting as proxy or controller and one leg
of the connection (my workstation).  Also, VNC would be an acceptable
protocol to use.

I've also tried the Remote Assistance tool provided by Microsoft, but it
fails when the client pc is behind a NAT firewall as the RA tool
utilizes the RFC1918 address assigned to the client workstation.