Here is some info from guys that race hundreds of miles in below 0 F temps. Good stuff.
Here's a few other sites with info from people who ride in the winter:
A couple of 'ultra' winter event sites
And the icebike site:
Machka & Rowan's Photo Gallery & Round-The-World Tour
And links to ...
Some of my favourite photo threads on Bikeforums
Monthly Photo Contests - List