Setup:
git init
git pull [email protected]:jkuan/config.git
git remote add origin [email protected]:jkuan/config.git
git submodule init
git submodule update

Making changes:
git commit -a -m "Useful commit message."
git push origin master

then on other machines:
git pull origin master

git submodules for vim plugins:
cd ~/.vim
mkdir ~/.vim/bundle
git submodule add http://github.com/tpope/vim-fugitive.git .vim/bundle/fugitive
git add .
git commit -m "Install Fugitive.vim bundle as a submodule."

to update submodules:
git submodule init
git submodule update