Here is a story of LTSP success.
http://searchenterpriselinux.techtarget.com/originalContent/0,289142,sid39_gci96\
1114,00.html
Some of the points may be helpful for schools.
I have put here some relevant portion from the news:
medical group has replaced its aging, mixed Novell-Windows desktop
environment with a bevy of thin clients running the Linux Terminal
Server project off a central IBM xSeries server.
The migration has resulted in a 30% cost savings and 100% uptime since
it was completed five months ago.
Taking into account desktop and network maintenance charges, Dr. Echt
initially expected to trim 10% to 15% off his IT budget by converting
to Linux.
The system no longer requires physical tech support. There's nobody on
the floors anymore, there's nobody running around troubleshooting."
"The beautiful part of it is if you have a problem at a workstation,
you will just check the port by swapping the component. It doesn't
have to be done by a tech person," Rosen said.
Ximian Evolution handles e-mail, local calendaring and the task manager.
OpenLDAP is the corporate address book and Webmin manages it.
The staff uses Mozilla to access the Internet and OpenOffice as its
productivity suite.
Rather than managing 200 desktops, Rosen's group keeps its eyes on the
central IBM xSeries server. They configured Zabbix, a free monitoring
tool, to watch the thin clients and connected it to a text paging system.
Once the conversion was done, there was some mop-up operations to do.
Once that was done, [we have been] five months error free," Dr. Echt
said. "No user complaints. No breakdowns. We are error free."