A free and open-source molecular graphics system for visualization, animation, editing, and publication-quality imagery.
PyMOL is scriptable and can be extended using the Python language.
Supports Windows, Mac OSX, Unix, and Linux.
A free viewing system for PDB coordinate files that runs on Mac PPC, Windows, Unix, and Linux systems.
Open source versions are also available.
A 3D graphics and molecular modeling program for the simultaneous analysis of multiple models and for model-building into electron density maps.