Well, when I stored my bike, I filled my tank to the extreme maximum, so no air can get in, drained the carbs, pulled the battery which is now hooked up to my battery tender plus(<- I highly recommend!), washed the bike clean, lubed and adjusted the chain, put it on its rear stand and threw a 4 soft rags under the front tire, that way it won't flatspot. After that I put a cover on.
I've heard of people spraying the inside of the cylinder with fogging oil against moisture.
When we parked floatplanes out in the cold, we used to pull the plugs and put engine dehydrators that would suck the moisture out of cylinders.
They turn from blue to purple when they're full.
http://www.sacskyranch.com/corrosion.htm
http://www.theultralightplace.com/dehydrator_plugs.htm