This is a program for looking at molecules in 3-dimensions. You can display a molecule in several different ways, from a wire diagram to a ball and stick or space-filling display, or using more representational displays which show the structure of the molecule. Using the mouse, you can rotate the molecule you're looking in any direction. The web site claims to have links to over 1000 molecules that you can download, spanning the whole range of biochemistry. There are also more advanced features included for researchers

The graphics in this program are great and its blazingly fast. The interface is quite easy to use, though a bit rough around the edges. This looks like a great program for students to use to look at the molecules that they're hearing about in class.

Computer: Just about everything

Source: http://www.umass.edu/microbio/rasmol/

Cost: Free