Hi Ben
I would recommend Knoppix as a very good starting point for a Debian
system.
It boots and runs from the CD, but does have a facility to install to hard disk. As an easy way to install Debian, I don't think you'll find anything better in it's price range.
Yes, PLUG mentioned this. It does sound like a good idea, although I get a nagging feeling that we wouldn't be doing it "properly" for some reason. Of course once we get started we can always try other distros too.
I did also wonder if we should start by dual booting them so that the windows facilities are still there and while we don't have it working completely the computers could still be used for everything they would usually be used for.
Regards Ben Francis