Howtoforge published a guide about setting with TALC on Ubuntu 7.10
>> Open-Source Classroom Management With iTALC On Ubuntu 7.10
This document describes how to set up iTALC on Ubuntu 7.10. iTALC is an open-source classroom management solution that lets you view and control other computers in your network. It lets you remote-control other computers, show the teacher's screen on all students' computers, lock workstations, send text-messages to students, power on/off and reboot remote computers, etc.
>> Open-Source Classroom Management With iTALC On Ubuntu 7.10