What is done with the toilet when a bathroom floor is retiled?

I'm thinking this is a project my boyfriend and I could do ourselves, however, I'm concerned about whether the toilet would need to be moved or lifted. If so, is there a simple way to do this?

Yes the toilet needs to be removed. As the first answer stated you should turn off the supply line and flush the toilet. Next, I always use a kerosene pump to remove any standing water in the s-bend and the tank. You can find a pump at most hardware stores for less than 5 bucks. Put a piece of cardboard in the tub (or shower) and unhook the supply line and closet bolts on the base of the toilet. Lift the toilet off the flange and carefully lay it on it's back, on the cardboard you placed in shower/tub. Now it gets kinda gross, Using an old or disposable putty knife, scrape the remnant of the wax ring from the bottom of the commode and the herkel ring on the floor. Sorry, Gotta happen. Lay your tile. If your tile raises your floor height dramatically you may need 2 new wax rings to re-install. One with flange and one without. Remember to get new closet bolts to re-install the commode. And while the unit is in the tub/shower it might just be time to put new guts in the tank at this time as it will be most convenient now.

Yes, remove the toilet from the floor. Install the tile being sure you have tile running up to the toilet waist pipe close enough so when you re-seat the toilet it is all covered. It is quite easy if the supply pipe comes from the wall. If it comes from the floor, it will just be another thing to cut tile around.
Make sure the tile is level as possible around drain pipe (waist) so when toilet is reseated it sits level and does not want to rock.
Mine had just a little unevenness so I put a few small clear rubber nubs you can buy at any discount store under the stool to keep it form rocking and protect the tile and stool from having porcelain on porcelain.

Sorry~ I thought you wanted to know about tiling where the toilet goes not how to remove and re install toilet. :(

You should remove the toilet if you are going to retile. Turn off the water supply, then flush the toilet, holding the lever down to drain as much water as you can from the tank. Next, remove the 2 bolts at the base of the toilet (might be under caps). Wiggle the toilet free, lift it off of the drain, and set it on a piece of plastic somewhere out of the way. Clean up the mess and stuff a rag in the drain to contain the sewer gas. When you reinstall the toilet, you will need to purchase a new wax ring. You can get this at any hardware store or home center. Hope this helps.

One other type of wax ring is a DOUBLE WAX ring found @ Home Depot. Not sure if Lowes carries them. It's only a couple bucks more, but worth it!