Computer programming has some important applications in biology. Viruses, proteins, hormones, and other molecular objects are modeled to better understand their function.

Computer modeling allowed researchers to invent a flu-inhibiting drug.
Here's a diagram of a computer model of the Garrett County bear population:
See the Bear Model home page for more information.
Medical imaging leads to better diagnoses and causes of disease.
Modeling and simulation of stellar processes helps astrophysicists understand cosmology.
Sky Draw, a Web application served from Italy, will compute and draw the sky for any time and location.
Here's the latest astronomy image from Harvard.
The Sweedish Royal Institute of Technology has a complete on-line course on Physics Simulation with Java.