How I figured out how to make a gradient follow a path (make a gradient ring) - Duh! :P

SO I USE CS3 at home and as far as I know you can not apply a gradient to a stroke... but I found a way.

First create a square in illustrator... and apply a gradient to it.

Open gradient options and create 5 colour boxes, blue at position 0%, green at position 25%, yellow at position 50%, red at position 75% and blue again at position 100%. Then angle the gradient at 90 degrees.

Now with the square selected go to Object, Expand. Expand Fill.

Then with the squat selected go to Object, Clipping Mask, Release.

Then drag the square into the brushes palette. Open the Art Brushes options and set the Colorization Method to None and the direction arrow to UP.

Now create a circle (stroke only) and apply the art brush.

Notes: Setting the art brush direction arrow to left or right creates a rainbow ring.