Best way to share desktop for instructional purposes?

I do a lot of teaching within SL. Most of the sessions are related to computer software - photoediting, animation, 3d modelling, etc. Up until now, I've been uploading screenshots of the interface and pointing at elements. It would be much nicer to be able to share my desktop with someone.

What's the easiest way to safely share a desktop with someone?
What's the cheapest way to do the same?

Most of my software will run under Linux, so I'm thinking a Linux Live CD with tightVNC installed. Can I run TightVNC over port 80 so firewalls don't whack it?

Is it better to use something commercial like GoToMeeting, Smart Technologies Bridgit, Webex or LiveMeeting? Is there a way to use these without spending a fortune?

Is there a way to stream the desktop directly into SL as a Quicktime movie? Is this workable given bandwidth considerations?

Has anyone else tried sharing a desktop application while teaching in SL?

-WW

There's something called Verosee for Skype which allows desktop sharing for $15/mo

Would streaming video clips be acceptable?

Camstudio seems to be a pretty nice app, records to AVI & converts to SWF. Don't know how good compression etc. is, but you could possibly do a little processing before presenting.

I think I have a solution. It requires two computers, one for Second Life and one for the Demos.

Ubuntu has a live CD which includes a VNC Server.

Gimp is already installed.
Blender installs very quickly.

The firewall could be configured to port forward 5900.
Application Start End Protocol IP-Address Enable
VNC 5900 5900 TCP <vnc.server.ip.address> X

Students would have to download a free VNC Viewer.
http://www.realvnc.com/products/free/4.1/winvncviewer.html

Students would also have to be running SL in windowed mode so they can see the demo.

The VNC server should be set to allow view only so the students won't have interactive control.
Using a Linux Live CD is nice because it reduces the risk of people getting in and messing up your system.

Camtasia should be able to stream live video to SL. It captures a certain size of your screen and turns it into a video stream. At least the version we have does it.

Here's the link to the website:
http://www.techsmith.com/products/studio/default.asp

Camtasia sounds good.

Snapz Pro works for Mac.
http://www.ambrosiasw.com/utilities/snapzprox/

Here's a video tutorial for making video tutorials using FrontCam.
http://www.blender3d.org/cms/Miscellaneous.477.0.html

Fraps should be able to make movies from any application.
http://www.fraps.com/

These still don't allow realtime viewing though. The movies have to be prepared ahead of time.