I would use a... Flamethrower :) From Freshmeat:

Flamethrower is a multicast file distribution system. It was originally created to add multicast install capabilities to SystemImager, but is designed as a stand-alone package. It works with entire directory heirarchies, rather than single files. It uses a server configuration file, which takes module entries similar to rsyncd.conf. It is an on-demand system; multicast of a module is initiated when a client connects, but it waits a predetermined period for other clients to connect before beginning.