I do not know too many on this group that do. However, it can be done and if you
go to Ubuntu Forums.
http://ubuntuforums.org/
You'll find plenty of people who do. Even people who got the touch screen
working.
You can check out the world of Utube
http://www.youtube.com/results?search_query=ubuntu+dual+monitors&search=

I was able to get them working. The only problem I have is that I may
have over-tweaked them. At first, the panels went all the way across
but now they stop at the first monitor. I may be responsible for this
by playing with the NVidia-settings app to much, but haven't been able
to find where that option is (there is a GUI for people using Fiesty
and the restricted driver from NVidia. Just type "gksudo
nvidia-settings").

There is a commercial option available for up to ten workstations per PC.
Check http://userful.com/products/dm

Ah I've done this in Windurs several times but not tried Ubuntu yet so
give me ten minutes and I'll let you know

hmmm not much luck so far So it's not as simple as it is with Windurs.

Well yes it's not easy to do it seems.

In Windurs all you do is plug another graphics card into the
motherboard and hook it up to anonther monitor and hey presto you have
dual display. In fact you can put in as many as you have slots for on
your motherboard. You don't need any fancy cards or drivers it just
works. Its been like that since win98.

So I thought this would be the same with Ubuntu. I've got a variety of
old cards which work and tried it. No luck :o(

I've even got it now with two identical PCI cards and the same monitor
to each output and the best I've seen is a tiny white spot on the top
right hand side of the other monitor. So I guess something has
happened but it's not really working :o(

I've got running my Ubuntu Edgy on dual 24" monitors. windows and mouse
go from one side to the other and I have specified the order of the panels
as well. I attach here a version of the XF86Config file for dual panels. You
will
just have to tweak it so it matches your hardware and the resolutions.