Circle movement

hello everybody outthere! im trying to build something with the cs3 flash demo…but i dont now really where to start…
so i got 5 or 6 heads…which move in a circuit, but this movement should not be 100% like a circle…sometimes a bit slower or faster and the heads should move a little bit from left to right on the x axis…
and when i try to click on a head, the head avoids the contact with the mouse…
please anyone outthere…can you give mie a hint …how o move these heads without tweening in circuit?

cheers

tayfun