Hi Tom, there's also another Sine wave script here for building the base shape:
http://moi3d.com/forum/messages.php?webtag=MOI&msg=1519.38

Then like Karsten says you'd use Transform > Deform > Flow to warp it into a circle. Draw a base line for the Flow right down the middle of the straight sine way from end to end, and draw a circle for the target curve. Then select the sine wave curve, run Transform > Deform > Flow then at the first prompt that says to select the base curve click on the line, and at the next prompt for the target shape select the circle.

- Michael