A good source for winter cycling knowledge is All Weather Sports out of Fairbanks, Alaska. I live in rainy Sitka, Alaska, where our major winter concern is freezing rain and not extreme cold, and I still consult the site for info on the best winter cycling gear. Also, many of the top riders in the old Iditabike/Iditasport and newer replacement races consult with owner Simon Rakower for the latest winter cycling techno-babble. Click the buttons on the bottom of the page for more detailed winter cycling information.
http://www.allweathersports.com/