Just a quick point of information that might saved time to some of you.
Installation of matplotlib is now pretty straightforward on Mac OS X 10.7 with HomeBrew.
Let’s say you want to install the last version :
$ brew install pkg-config
$ git clone git://github.com/matplotlib/matplotlib.git
$ cd matplotlib/
$ python setup.py build
$ sudo python setup.py install
The dependencies of matplotlib (libpng, freetype, etc) are all present in /usr/x11/lib, however they are not found via the installation process because of the absence of pkg-config on Mac OS X. By installing it with HomeBrew, everythings falls in place.
Thanks to Telliot99 for finding that out.
You can read the original blog post at : http://telliott99.blogspot.com/2011/07/matplotlib-on-os-x-lion-revised.html
pkg-config could be installed from source or via macport, just make sure the search path is configured correctly to include (this what HomeBrew actually does) :
To get more information on HomeBrew, visit : https://github.com/mxcl/homebrew