Herd is a single-command Bittorrent-based file distribution system, based on Twitter's Murder. It was designed for pushing code out to a number of production systems. You can probably use it for other things.
Herd requires no extra Python modules on the destination system as it ships around its own (lightly modified) copy of BitTornado.
Murder was Twitter's original BitTorrent-based file distribution system. It's pretty dependent on Capistrano and requires that a separate tracker process is started before you run the deploy task.
Herd is run by a single command, which spawns its own tracker in the background. This makes it really trivial to integrate into whatever deployment system you like.
Herd needs Python > 2.5 and eventlet (on the source system only). All other libraries are shipped with it. To install eventlet, you can just do:
easy_install eventlet
Herd assumes that you're running as a user which has passwordless SSH access, with the same account, to all the machines you need to copy to.
Create a file hosts.dat with a list of the hosts you want to copy to, and:
herd.py ./myfile.tar.gz /path/to/destination.tar.gz hosts.dat