Installing nltk on Mac OSX Lion

Recently I needed to install nltk, it was giving me errors regarding YAML not being installed. In a Python-virtualenv environment, the following did the trick:

$ ls
bin include lib
$ bin/pip install pyyaml
$ bin/pip install http://pypi.python.org/packages/source/n/nltk/nltk-2.0.1rc1.tar.gz
$ . bin/activate