I use Fedora Core 4 on my kids' machine. It comes with
lots of edutainment software built in, and is easy to
setup and maintain. I have been able to modify and
install software easily though CVS, YUM, and RPMs.
Once you have a Linux machine running there isn't
much to do to it, unless it fails. If you create an
image of the install and build a bootable CD from that,
the repair of any failed machine would be to replace
the bad part and reload the image. All new machines
could be ready in just a few minutes.
Some of the reasons I would suggest Linux over Windows:
First: Cost. Windows XP will run $60/machine
(School/non-profit pricing), but will not run very well
on anything lower than a 500Mhz. Let's face it, most
schools use 5 year old tech that is donate from companies.
Second: Education. Using Linux allows the kids to see
another OS besides Windows (which they likely use at home).
Third: What wil the teachers actually be doing on these
machines once they are setup?
Probably not much.
Fourth: Tux plushies are more cuddly than windws. :)