You need a ratchet with a spark plug extension on it (long socket), and an extension. You may also find it useful to use a 'universal' joint extension rather than a straight extension as it allows you to use the ratchet at odd angles. Can pick these up an adequate ratchet set at kmart for about $15, and teh universal adapter is about another $5. Take off both left and right fairings. You should be able to access the spark plugs from the side - if you look below the frame you should see 4 cables entering the top of the engine, at the end of these cables are the spark plug caps. Pull these off and you will reveal the spark plugs. Make sure you keep track of which cable goes to which plug! You may even want to label them if they are not already labeled. Take your ratchet and put this where the plug cap just was - it will take a bit of fiddling to get the socket on the actual spark plug. Remove that one. Repeat for all 4 plugs. You may have to bend your hand in odd positions at times, but it will work. Do this process in reverse to put the new ones back in. When putting the spark plugs back in only do them up so they are firm (not tight). You do not want to strip the threads in your engine.
