Here's a link to another site that has a good article on overwintering. It's at the bottom of the page I linked you go.
I live in OH, and like musky, my goal is not production during the winter, but simply to keep them alive. I pull them out of their pots and prune both the branches and the roots so that they are significantly denuded of small branches/roots/leaves and so that the distance from the soil line in both directions is equal. I then repot with fresh soil. At this point, ideally you will keep them cool and not well-lit, as the goal is for them to go dormant. Also, don't water or fertilize as frequently as you do during the grow season. (Note some people actually put their OW's in a closet or shed so they get no light. I don't do that as I'd likely forget to water them at all.) Some time in the early spring, though, start upping the light/watering/fertilizer so they come out of dormancy. But watch out - this is also the time "hidden nasties" may start to appear. "Hidden nasties" include aphids! Yes, I buy ladybugs and let them loose in my house - they just love eating aphids and aphid eggs.
Unlike musky, I grow exclusively in pots, which makes it easier to overwinter the plants. But of course, you can always dig them out of the ground - your choice.
If your goal is to keep them like houseplants during the winter, I'd still suggest giving them fresh potting soil, then just bring them inside and reduce your fertilizing. Key to watering is still either the weight of the pot (much lighter than when you first water) or let the leaves droop just a tad. Let the plants tell you when they want to be watered.
If your goal is to keep production up, then you've got to buy lighting and such, and I've chosen not to do that so won't comment on it. Let us know if this is an option though, and someone with experience doing this can weigh in.