To grab all the dependencies, either:
git clone git://github.com/ollez/emacs-dot-d.git
cd .emacs.d
git submodule init
git submodule update
or on git v1.6.5 or later:
git clone --recursive git://github.com/magnars/.emacs.d.git
The first time you start emacs, it will install some additional packages that are best handled by the package manager.
I use Cocoa Emacs, installed like this:
brew install emacs --cocoa
You can also get the very latest Emacs:
brew install emacs --cocoa --use-git-head --HEAD