git-1.6.6 is assumed (at the time of writing)
pretty simple:
$ sudo aptitude install build-essential
$ sudo aptitude install zlib1g-dev
$ mkdir ~/Downloads/git
$ cd !$
$ wget http://kernel.org/pub/software/scm/git/git-1.6.6.tar.gz
$ tar xvfz git-1.6.6.tar.gz
$ cd git-1.6.6/
$ ./configure
$ make
$ sudo make install
$ git