PyFITS provides an interface to FITS formatted files under the Python scripting language and PyRAF, the Python-based interface to IRAF. It is useful both for interactive data analysis and for writing analysis scripts in Python using FITS files as either input or output. PyFITS is a development project of the Science Software Branch at the Space Telescope Science Institute. PyFITS and all necessary modules are included with the stsci_python distribution and associated updates to it (though what is included there may not be the very latest version). PyFITS does not require PyRAF however. It may be used independently so long as numpy (or numarray) is installed.
The manual provides a tutorial on how to use PyFITS with FITS images and FITS tables, along with an extensive description of all the methods (currently) available for working with FITS files. This manual, however, is only a DRAFT document and is very much a work-in-progress.
The current version of PyFITS is v1.3 (2008 February 22).
Download here at: http://www.stsci.edu/resources/software_hardware/pyfits/Download