Larger Tires on a Jeep……..

I have an “05” Jeep Wrangler, I would like to put larger tires on it 1 maybe 2 sizes bigger, with a 1-2 inch suspention lift. How will this affect my MPG? Will it have an affect on the drive line (i.e.: drive shaft yolk, Rear, Transmission)? What are the pros and cons?