I want to change the spark plugs on my 2006
My best advise - don't waste your time. Check the manual and I think you will find that the plugs won't need to be changed for a while. The bike has 2 plugs per cylinder (4 total) and will require you to take the tank, some gas lines, and a few other odds and ends off the bike before accessing the plugs. The plug wires might get damaged if you pull them off roughly. The more often you pull them and re-attach them, the sooner you will have to replace those too. You will need a spark plug wrench (socket) or the one from the tool kit that came with your bike (ha ha) that will hold the plug as you pull it out from between the valve covers for the overhead cams. Turn the spark plug on the axis, don't put any bending force on it. This is also true when putting in the new plugs. Side force will crack the ceramic. Also, the threads are fine so don't cross thread the plug into the cylinder head - this will make it difficult to get the plug in right and might cause lost compression/engine power. Also make sure the area around the plug is clean and dry so no dirt falls into the cylinder when you pull the plug. Also, turn off your tank valve before pulling the tank off (if a valve is on that model).
I am sorry to say, the tone of the question just makes me want to say, please don't do this yourself. Wanting to change plugs and needing to change plugs are two different things. Also, asking if it is difficult vs. knowing that you have the experience to explore a bit to see for yourself (take the parts off to see where the plugs are) makes me think you haven't done this before.
If you live in the northeast US, enjoy the warm November and ride instead of work on the bike. Let the dealer take care of it when it is needed. Doing it early doen't make your bike last longer or give it more power. It just takes time and money from other things you could be doing.
If you want to do it to spend an afternoon learning about your bike, go ahead and take some parts off and see where the plugs are. If it is easy and you have the the tools, it won't hurt anything to pull the wires, unscrew the plugs and check to see if they are black, full of soot, the electrode is eroded away or, hopefully, the look a nice light carmel color of a well used and well tuned engine. If they are nicely colored, put them back and keep riding. Make sure you get your tank back on and the fuel line connected well.
Good luck and let me know what you decide to do.