Easiest way would be to take tire & wheel to a tire shop and have them break it down for you. You probably won't have to completely remove the tire, just break the bead seal on the valve stem side. Here in my neck of the woods you'd get charged 5 dollars at the most.
If you must do it on site, you really need some specialized tools. There's ways to do it without the tools, but it's a hassle. Basically you have to put a lot of pressure on the bead of the tire to break it loose fom the rim. I've heard of guys driving over tires to break them loose, prying with a screwdriver or large chisel, using sledge and flat iron, using FEL and carefully placed wood block. All kinds of ways to break them loose, all kinds of ways to damage tire or wheel. If you do have to remove the tire, you first break it loose on both sides. Then press one of the beads into the center depression of the wheel while you use screwdrivers or tire irons to pry the bead off the wheel rim opposite of where you pressed it into the depression. The depression gives you the room to pry the bead over the edge of the rim. You'll need a compressor with air tank to get the bead reseated afterwards. Personally, I don't see any way it would be easier then having it done.
Dave