The open source Linux Terminal Server Project (http://www.ltsp.org/) has put together some easy to use packages that make use of the remote desktop facilities built into X that allow you to create simple and inexpensive thin client solutions using Linux.
Programs run on the central server, but are displayed on the desktops of disk less client systems that boot from the network. The clients can be striped down thin client computers, or just recycled older desktop systems. The result is simmalr to Ctrix or MS Terminal server, but with better perfomance and stability, at a fraction of the cost!
I will go over the theory of how it all works, and show how to configure the server. Then we will boot up a client and try out some desktop applications to see how well it performs.