|This code has been put under version control in the project Pymol-script-repo|
MSMS is an excellent tool for computing protein solvent excluded surface (SES). MSMS Plugin for PyMOL provides a graphical user interface for running MSMS and displaying its results in PyMOL. Most recent MSMS Plugin code can be obtained from this link.
The most recent code is maintained by the original author on github: MSMS Plugin for PyMOL @ GitHub