No, you don't need to winterize it. Of course, what Simnitro is talking about is maintenance, and the more you use a boat (or car), the more maintenance it needs.
IF you're ONLY going to use the boat once/month, you might consider jacking up the trailer to keep the tires from getting out of round from the weight. If it's at home, you can just move it a few inches and resolve the issue.
Don't forget your water pump impeller.