Change Your Oil - Letting dirty oil sit for long periods of time creates sludge. You do not want this building up in the bottom of your engine. Change the oil before letting your bike sit for the winter. There is no real need to change come spring, but it's your choice. Lots of people will start out with the oil they put in last Fall. The cost is minimal in terms of money and time. Your choice.
Add Fuel Stabilizer - Add fuel stabilizer to your tank and fill with gas. Sta-Bil is the most common used stabilizer. Put it in at the gas station and then fill the tank to the top. By the time you get home, the Stabl and gas are well mixed and its into the carbs and gas lines.
Drain Your Carbs, Theory 1 - I think it was in Andrew MacDonald's Q & A column in Rider where he suggests not draining the carbs since with less liquid, it will just evaporate, and therefore varnish up, that much quicker.
Drain Your Carbs, Theory 2 - This is not the same as running the bike until empty. This leaves a small amount of fuel in the carbs. Fuel in the carbs will eventually evaporate. This can leave behind varnish that plugs jets and causes floats to stick. The theory behind draining your carbs is to drain out ALL of the fuel. If there is NO fuel in the carbs, there is nothing to evaporate and varnish up the carbs.
Tires - Inflate the tires to recommended pressure. Store the bike on its center stand.
Coolant - Check and (optionally) replace the coolant. If it's not reasonably clean, coolant can contain acids and sludge which will cause rust over time. Coolant should be replaced every 2 years, right before winter storage is a great time to do it.
Wash The Bike - Dirt attracts moisture. Moisture creates rust. Put your bike away clean.
Cover Your Bike - This is optional, but many like to do so. Helps keep dust and dirt off your bike while letting it sit.
Rodent Protection - This will be left up to you to decide how to prevent. But you would not be the first person to store their bike for the winter, and come spring, find mice have been nesting in your motorcycle.
Battery - the following details were plagiarized from the Yuasa web site.
If the vehicle is in storage or used infrequently, disconnect the battery cable to eliminate drain from electrical equipment. Charge the battery every two weeks.
For extended storage, remove the battery from the vehicle and charge to 100%. Charge the battery every month if stored at temperatures below 60° F. If stored in a warm area (above 60° F), charge every two weeks. Make sure batteries are stored out of reach of children.
Use a Battery Tender. A Battery Tender will keep your battery properly maintained. The Battery Tender brand chargers will contain a microprocessor that will fully charge your battery and then automatically switch to float mode. If you have connections on your bike, there is no need to remove the battery. Just plug in the Battery Tender and leave it all winter long.