I see this question is quite old, but its still unanswered too, so for the sake of newcomer rubyist:
first step of installing anything on Fedora is to upgrade it to Ubuntu :)
Great Debian/Ubuntu AMIs aere referenced at http://alestic.com/
You will solve yourself a lot of administration pain.
It wont solve the Ruby pain though as Debian is a brain damaged with regards to Ruby/Gems.
there are a couple of things you can do though (on both debian/ubuntu and fedora)
I posted an Ubuntu AMI bootstrap script from an oss project I'm working on at http://gist.github.com/307730
Not everything there is relevant to you but I've burned my hand so typing singlehandedly :), can't do much editing. its structured and I hope is easy to understand.
another thing you can try is installing rvm (http://rvm.beginrescueend.com/) I'm considering adopting it myself as a proper multi-distro solution to ruby pains.