Update 8/30/2013: The link below no longer works. Follow the directions on this page to install a fortran compiler on your mac. Or install Scipy Superpack, which comes with a fortran compiler. You can get it here.
I ran into an error installing Scipy today, saying “error: library dfftpack has Fortran sources but no Fortran compiler found”. After a little digging, I found a fortran compiler here: http://r.research.att.com/tools/. Installing that fixed the problem and allowed Scipy to finish installing.
Note: I also ran into a “error: could not create ‘/Library/Python/2.7/site-packages/scipy’: Permission denied” error after that, which I worked around by using sudo for the install.
I’m including the actual error messages so anyone searching for those messages will find the solution quickly 🙂