It isn't that common with us yet, although it is starting, our Finance Assistant has a pair of 17" ones then she can keep ParentPay open in one all day to speed that part of her job up and then does her normal job in the main screen. Myself and my technician have dual widescreens and I have a laptop as well for a 3rd when needed. The Assistant Head who is the timetabler has just this last term got a new 22" TFT and kept her 17" one and has found it made her life 100x easier doing the big work on the timetable, now fine for the rest of the year it will probably not be that useful to her but it did make it better for the TT which is a key part of her job.
IWB PCs in classrooms are all setup where possible as dual splitting screens to allow staff to use the MIS away from the students eyes.
Our finance staff have two monitors. A few other admin staff have 24ins monitors as it makes doing massive spreadsheets a ton easier.
We have dual 23ins monitors, mostly because it allows us to VNC/RDP into a machine and still do stuff on the other screen. The kids always find it amazing that you can drag stuff across to a different monitor.
A number of the Web team at the LA are dual screen but few others are, and this is across most departments.
I work over 2 machines, the council desktop has one screen and I work on a laptop connected to an additional 27" screen, so effectively I work on 3 screens.
Mainly each screen is used for different tasks and saves a lot of switching virtual desktops (which I still do some of anyway).
I am an exception though ... and most schools I have been in it is rare to see 2 screens, but more common for a single large screen instead. It all depends on how you work and separate different tasks I suppose.
Blimey you lot are light years ahead of us...the muppets here barely cope with one screen let alone two...most of them haven't even got the hang of zooming in and out in apps to see more...as for minimizing or multi-tasking, well...when I say "just fire up IE" they feel the need to close everything else down before they open the new app...
The laptops in classrooms can be used with the IWB and laptop screen separate but then they just get confused when the cursor vanishes off the laptop screen.
I am hoping that the new young teachers that hopefully will start to replace the dinosaurs will be up for this sort of tech...
...mind you I don't know where I am going to find the money to buy all these monitors!
I did have two 24" and a stonking good PC however now use a laptop and 24" with a docking station. Our SBM does the same. The only other person who has dual screens is our cover lady for SIMS cover.
We've got dual 17" monitors here in our office, which does seem to amaze everyone who walks in, and is astonishingly useful. If you're a techie with only one monitor then you I'm afraid that, frankly, You're Doing It Wrong. Having an RDP on one monitor and your desktop on another is so unbelievably useful.
Any classroom that has 22" widescreen monitors also has dual monitors as well - one widescreen and one 17" square that clones to the projector. It seemed wrong to give all the students a 1920x1080 widescreen monitor and leave the teacher with 1024x768!
We have dual screens in the ICT suite (24 workstations), plus a few dotted around and of course I have in my office. Dual screen and Win7, what a combination :-D.
No one here has twin screens, although I was thinking about doing it. At the moment I use an old laptop as my second screen.
In my last school, most of SMT had an additional screen to go with their laptop. At my current school, most of the staff are in the same category as those @CESIL has, so I haven't felt the need to offer any additional screens here - and we don't really have the money anyway.