To install on a Mac run:
git clone git@github.com:ericbarnes/Sublime-CodeIgniter.git ~/Library/Application\ Support/Sublime\ Text\ 2/Packages/Sublime-CodeIgniter
To install on Linux (tested on Ubuntu 10.10 x86, 11.10 x86) run:
git clone git@github.com:ericbarnes/Sublime-CodeIgniter.git ~/.config/sublime-text-2/Packages/Sublime-CodeIgniter