How to install lxml on Ubuntu
Since you're on Ubuntu, don't bother with those source packages. Just install those development packages using apt-get.
apt-get install libxml2-dev libxslt1-dev python-dev
If you're happy with a possibly older version of lxml altogether though, you could try
apt-get install python-lxml
and be done with it. :)
I also had to install lib32z1-dev before lxml would compile (Ubuntu 13.04 x64).
sudo apt-get install lib32z1-dev
Or all the required packages together:
sudo apt-get install libxml2-dev libxslt-dev python-dev lib32z1-dev
As @Pepijn commented on @Druska 's answer, on ubuntu 13.04 x64, there is no need to use lib32z1-dev, zlib1g-dev is enough:
sudo apt-get install libxml2-dev libxslt-dev python-dev zlib1g-dev