How do I remove rust from my cast iron cookware?

This is another subject for which there are many opinions.  I attended a cast iron cookware care and cleaning seminar at one of the primitive rendezvouses and we were told that you can use CocaCola - the acid and carbonation supposedly eats the rust away.  I didn't drink a soda for a couple days! 

You can probably find old cast iron cookware at garage sales and antique stores, and even though they may be rusty, they can clean up pretty good and be very functional.  Of course, we would rather you buy brand new cookware from us, but hey, we're here to help.