Utility to push/multicast multiple files to multiple windows systems on IP Network

I have a classroom with 24 workstations setup in it.  These systems have a base load of Windows XP with Service Pack 2 and all current updates.  They are running VMWare Workstation 5.5

I have a server in my lab, located one floor down from the classroom.  I need to find a utility that will allow me to have some type of listening client on the workstations in the classroom.  I also need a companion app that I could load on my server in the lab that will send files to all of the workstations in a "push" or "multicast" method.  

For example, a class is coming up.  The instructor has built a VMWare image and I have the files for it on my server.  I then want to be able to push these files up to all of the workstations in my classroom as efficiently and easily as possible.  

Currently, I have been configuring one of these systems in my lab with the proper VMWare image files and then using Ghost to create an image of it.  I then use a Ghostcast session to load all of the systems at once.  This seem inefficient considering I don't need to push the OS everytime.  The only thing really changing is the VMWare files.

Any ideas?