Welcome to BYC. Glad you decided to join our flock. Definitely check out the links that TwoCrows has given you. Please feel free to ask any questions you may have. We are here to help in any way we can. What kind of chickens do you have, and what kind are you looking to get?
Some important things to keep in mind when winterizing coops:
A thick layer of bedding on the floor helps keep the coop warmer due to its insulating abilities.
Good ventilation is essential! You don't want obvious drafts, but nor do you want to seal the coop up tight. Ventilation helps reduce moisture levels (not to mention ammonia levels), which makes frozen combs/wattles/feet less likely to happen.
Chickens can usually stay adequately warm in cold temperatures provided they are out of the wind. If wind gets into your coop or run, I would use some plastic to block the wind flow. My coop's run is made of wire, so I just staple a plastic sheet to it on chicken-level. That way, there is still ventilation, but the chickens don't have wind blowing directly on them.
Be careful if you heat the coop. Heat lamps and heaters have been known to catch fire, sadly destroying the coop and chickens in it. If you decide to use a heat lamp, make sure it has a heat-shield in front of it, and securely attach it to the ceiling. Floor heaters are a little safer, but I would still be careful about having them touch too much bedding, or putting them in a place where the chickens can get into contact with them. In one of my coops, I have a small space heater on the floor. To prevent contact with the chickens, and to a certain extent, the bedding, I constructed a hardware cloth "cage" around it.
What kind of chickens do you have? Did you choose cold hardy types?
I have Buff Orpingtons and they managed pretty well last winter, even with those horrible negative temps we had.
I do the same thing posted by Bantamlover. I put plastic around my run and the chickens go out all winter but no wind or snow is blowing directly on them. If you do that just make sure there is ventilation on top otherwise it'll be like a green house, lol.
I can't give any advice on heating the coop. I don't want to do that for risk of fire, but also if the chickens get too used to the warmth and then you lose power they wont be as acclimated to the cold as they would have been without the heat.
It's a constant learning experience having chickens.