I recently had some struggle to build and install SciPy 0.8.0 on Mac OS X 10.6 Snow Leopard, but actually it’s quite easy.

I used the instructions on scipy.org and the HJBlog as source. Since there are builds of NumPy 1.5.0 for Python 2.7 available, you don’t need to install fftw and umfpack manually.

You only need to install gfortran from this site. Pick the latest build for Snow Leopard (e.g. this one).

Next, install NumPy with the disk image from SourceForge or with pip:

$ pip install numpy

To build and install SciPy, download the latest version from SourceForge and do the following:

$ tar -xf scipy-0.8.0.tar.gz
$ cd scipy-0.8.0
$ export CFLAGS="-arch i386 -arch x86_64"
$ export LDFLAGS="-Wall -undefined dynamic_lookup -bundle -arch i386 -arch x86_64"
$ export FFLAGS="-arch i386 -arch x86_64"
$ export MACOSX_DEPLOYMENT_TARGET=10.6
$ python setup.py build
$ python setup.py install

Everything in one command:

$ CFLAGS="-arch i386 -arch x86_64" LDFLAGS="-Wall -undefined dynamic_lookup -bundle -arch i386 -arch x86_64" FFLAGS="-arch i386 -arch x86_64" MACOSX_DEPLOYMENT_TARGET=10.6 python setup.py build install

I hope this works for you as well as it did for me.