Its pretty easy, just make sure you have a torque wrench handy. Also I would invest in a clymers manual if you dont already have one. Basically...drain the coolant from the cylinders.. remove the head and throw away the head gasket, remove the cylinders. Then pull the clips out on each side of the piston... take a socket extension and put in the side of the piston and beat the little rod thingy out (cant think of the name of it)... pull the pistons out... do the reverse of what you just did to put new ones in.. also make sure the arrow on the top of the piston points towards the front of the bike. Put the rings on with the writing facing up, and line them up with the pin in the piston... slide the cylinders back on and use a new base gasket, put the head back on with a new head gasket.. torque everything in its proper order and to spec.... and your done.
Best advice though is to get a cylmers manual it walks your through the entire process with pictures.