rsync to multiple remote servers

Turns out there is a program that permits this, just not the original rsync program. It's called pssh (parallel ssh I suppose)

One of the features:

"-- Parallel rsync (parallel-rsync, upstream calls it prsync), efficiently copies files to multiple hosts in parallel"
- http://www.ubuntugeek.com/execute-commands-simultaneously-on-multiple-servers-using-psshcluster-sshmultixterm.html

No, there is no way in rsync to specify multiple destinations. You'll need to invoke the command multiple times. If you have many targets, you might want to consider using a network filesystem instead--it might be a better fit for your problem.