Hey folks,
There's now a gem for s3sync on RubyForge. With it, you can install the latest with:
sudo gem install s3sync
... which will give you /usr/bin/s3sync and /usr/bin/s3cmd executables.
http://rubyforge.org/projects/s3sync/I'm coordinating with ferrix for him to take this over, or at least be the main dude. Just wanted to get it gem'd up so that it's easier to install as I install the rest of the Ruby tools I use.