I know my Boston fern will die when the weather freezes. What can I do with it so it will come back out next Spring?

Boston ferns are usually an inside plant, unless you live where it is warm all the time. But you are worried about freezing, so I will assume that you do not. Take it inside once the weather gets below 45 degrees and keep it inside until it warms up in the late spring. If it does freeze I do not think there is anything you can do to bring it back to life.