SHARP is a program for heavy atom refinement. It typically produces maps of higher quality than other programs of its kind. It has a web-based interface that either makes it really easy to run, or gets in the way, depending on your point of view.
You can learn more about SHARP at the developer's web page.
To run SHARP, you need a SHARP account, which can easily be made for you by the current SHARP administrator. As of 10/01 the SHARP administrator at UCSF is: