Bezier Curve Demo : www.math.ucla.edu/~baker/java/hoefer

Just click four times anywhere on the screen, these are the control points. A bezier curve will be drawn for you. Now you can click on any of the four points that you have already created and drag it around. Notice how the Bezier curve is redrawn according to the new control points. The button is self explanatory. Have Fun!!!
P(t) = (1-t)3 P0 + 3(1-t)2 t P1 + 3(1-t) t2 P2 + t3 P3