I have many machines which require the same configurations. My goal is to boot them all from the network and load a virtual machine. It would be wonderful to have one image for all of our customer service machines. That way, I could load the virtual image, perform updates, and know the next time they boot up they will have all the changes. Ideally, the machines would store the image locally and only download a new image if there has been a change.

With all the information out there on "desktop virtualization", "PXE booting", and "virtual machines", I feel lost. I have been reading for hours and feel like I have only just scratched the surface.

I would like to do this using open source or free software. Any suggestions?