iTALC, or Intelligent Teaching and Learning with Computers, is a didactical tool designed to assist teachers. Despite its name, the tool itself isn't a learning environment. It's meant to let teachers control their students' computers in a computer-driven classroom setting. Thanks to its powerful remote desktop control features, simple setup, and lack of cost, it's a potential remote assistance tool for any type of network.
iTALC is cross-platform and easy to install. There are binary packages and installation instructions available for several Linux distributions, including Debian, Ubuntu, SUSE, and Gentoo. You can also download the source package. I set up iTALC in Fedora from source without any issues and managed clients running other Linux distributions and Windows XP.