How could does it get where you are?
Here in the UK it rarely gets cold enough to cause a problem but its still adviseable to winterise. You need about 5 days of constantly below freezing temps both day and night) before water in the engine will freeze.
I'll be winterising mine soon and here's what I'll be doing :
Run the engine up to temp.
Drain engine oil, fill with fresh oil and new filter.
Do same with gearbox / V drive if required
Add fuel stabiliser to the tank.
Remove the intake hose and run about 5- 10 gallons or water / antifreeze mix through the engine. This will pass through the V drive, tranmission cooler, raw water pump, engine circulating pump, engine and manifolds.
While the engine is still running add engine fogging oil down the intake till it stalls (on a MPI engine you'll need to remove the plugs and add some down the bores).
Next there are two lines of thought. Some believe that leaving the water/antifreeze mix in the engine has anti corrosive properties and is best. The other option is to now drain the block, manifolds and hoses thinking that is there is no fluid left there is no chance for it to freeze. (this is what I do).
Grease up rudder, steering, control cables
Apply lashings of WD40 etc to all electrical contacts, engine etc.
Cover and store.
Other options if you plan on using the boat over the winter include adding a 5W light bulb to the engine compartment. Turn this on over the cold spells and the heat will prevent the block from getting cold enough to freeze the coolant. Ideal if you fancy a quick bit of boarding without having to re - winterise after each outing.
Some people also cover the exhaust outlets to stop rodents crawling up there
