I found these mathematics video lessons on YouTube when I placed my latest tutorial on circular flash preloading animations. They really do a good job of explaining how some of the stuff we see in programming is doing what it is doing.

Part 1: Circular Functions Part 1 of 3

Part 2: Angles and Their Measure Part 2 of 3

Part 3: Angles and Their Measure Part 3 of 3

The professor giving the lesson is good at explaining mathematics. YouTube is a great place to learn.