How do I rotate the camera around an object?

Hey all, I found some great simple source code for cube environment mapping that uses GLUT :smiley:

http://shogun3d.net/pages/opengl.html

I am having trouble modifying the program so that the camera rotates around the object. This source code just rotates the object with a stationary camera, which is missing half the fun of this sweet graphics technique. Can anybody help?