PyMOL is a user-sponsored molecular visualization system on an open-source foundation. Please support development of this open, effective, and affordable software by purchasing a subscription to maintenance and/or support. While a subscription to PyMOL gives access to pre-compiled binaries, you can freely download the latest source code tarball (version 1.4.1 as of December 8, 2011) here.
Once you have downloaded and unpacked PyMOL sources,
pymolto build the source code.
In the following links you will find instructions to build PyMOL from source on different platforms:
After successfully installing PyMOL, you will need to move the PyMOL executable in your executable path, or update your
PATHenvironment variable. Alternatively, you may point the
O3_PYMOLenvironment variable to the PyMOL executable before running Open3DALIGN, or use the
env pymolkeyword in your Open3DALIGN script.