This will get Feedbin running on a fresh Mountain Lion install. If you already have a ruby environment configured you can skip most of these steps.
These can be downloaded from the Apple Developer website, or in XCode preferences.
ruby -e "$(curl -fsSL https://raw.github.com/mxcl/homebrew/go)"
brew update
brew install rbenv
brew install ruby-build
echo 'if which rbenv > /dev/null; then eval "$(rbenv init -)"; fi' >> ~/.bash_profile
source ~/.bash_profile
rbenv install 2.0.0-p247
rbenv global 2.0.0-p247
gem install bundler
cd ~/Downloads
curl -L http://postgresapp.com/download > postgres.zip
unzip postgres.zip
mv Postgres.app /Applications/
open /Applications/Postgres.app
brew update
brew install redis
Make sure to follow post install instructions.
git clone https://github.com/feedbin/feedbin.git
cd feedbin
bundle
rake db:setup
bundle exec foreman start
curl get.pow.cx | sh
ln -nfs /path/to/feedbin ~/.pow/feedbin
At this point you should be able to load feedbin.dev in your browser.