Xmodulo posted a tutorial about booting a diskless Linux machine

Imagine you have 30 computers in your office, all of which need to access the same application. If you are managing the computers as an administrator, what would you do? It will be a waste of your time if you install the application on every computer. On the other hand, a diskless system can eliminate the problem. With a diskless system, you just need to install the application on a central NFS server, and then boot all 30 clients over network.

  How to diskless boot a Linux machine