Dennis Rodman -- Fire Up the Popemobile, I Got BIG PLANS for the Vatican

Dennis Rodman plans to take a spin in the Popemobile during his trip to Rome ... but he tells TMZ, that's only the BEGINNING of his plans to change the world by meeting the new Pontiff.

Rodman was at Miami International Airport yesterday -- where he boarded his flight for Rome -- and we were able to fire off a bunch of questions before he took off.

Among the highlights ... Rodman discusses the most surprising thing he experienced in North Korea (involving a mummified Kim Jong Il), how he plans to broker peace between North Korea and the U.S. and what his agenda is for Vatican City ... we weren't kidding about the Popemobile.

But our favorite part ... Rodman tells us who the "pimpest" Pope of all time is.