I'm looking for a video conferencing application that would be used primarily for remote support and application demoing.

Here is what I need

1. I send a link to a person and via their browser they log into a 'meeting' and either I share my screen with them or they share their screen with me. In addition I might need to take control of their screen if they grant me that right.

2. Can not require there be any setup by the person on the other end, and needs to be able funtion through a firewall - ideally just use port 80 - the people I'm dealing with generally are computer literate, but are not the system admin, and can not alter the corporate firewall settings etc.

What would be the best solution?

Thanks

Gnome meeting. Google it, and be amazed.

From what I read in the GNOME Meeting FAQ it does not do desktop sharing, and control which is what I really need. The video cam and VOIP is really not of any interest for me. I'm looking for something to do on-line demos and tech support.
I presently use an IBM Sametime service provider, but would like to get something that will run on my Linux server.

KDE has a desktop sharing option. I don't know about Gnome however. You may need to use VNC. A VNC server runs on the desktop being shared, and a VNC viewer is run on the other computers. (vncview to view a linux desktop, rdesktop to view a shared XP desktop using XP's)

This webpage explains how this is done at a University math lab:
http://math.hws.edu/eck/about_linux/vnc.html

The option of having them download and install an application is not an option. Most of the people I deal with are behind a firewall and would have to get permission to install software on their computer. The VNC solution would work well if I controlled both ends, but I don't.

I have found a couple service providers that rent time on their server, and this might be the best way for me to proceed, but I would like to have it all under my direct control.

There are three programs for whiteboard/desktop sharing.
Microsofts NetMeeting for windows. Irix's SGIforum, and the X windows program SunForum. They use the T.126 protocol. Googling for 'T.126' in quotes may provide more answers for you. (Which is how I found out the information on these programs)

I think that this is the standard way of doing what you want to do.
These three programs should be inter-operable, so you can use SunMeeting to conference with someone using a NetMeetiing3 for example.

Here is the URL for the SunForum datasheet: http://www.sun.com/desktop/products/.../datasheet.pdf

However I don't know of any realtime Desktop -> Webpage programs that you seem to be hinting of.

I think this answers you question

WebEx?