I have one cast iron pan that I have only used a couple times in the first few weeks of the five years I have owned it. Apparently I didnt do it right. Would some one point me to an idiots guide to using cast iron, cast iron that I let get rust on?
If it's only lightly rusted, I've had luck using kosher salt to scrub the pan free of it, so it removes as little as possible of the seasoning. If not, you can use something more robust like steel wool, then season it again.
As for using it to cook, I don't do anything different while cooking on cast iron than I do any other pans, really. Just a different care treatment afterwards for cleaning.