iTALC is a powerful didactical tool for teachers. It lets you view and
control other computers in your network in several ways. It supports Linux
and Windows XP (Vista/7 soon) and it even can be used transparently in
mixed environments!

For setup instructions check INSTALL file in /usr/doc/italc-*/

To my understanding, after the setup of keys to run italc as teacher
you also must start ica.
