I have to agree with some posters, I was fearing my first winter commuting, but I'm finding that it's actually quite enjoyable. The cold is not a problem at all, just keep moving! Goggles were probably my best comfort item, before that I had steaming up glasses and my eyes teared up a lot.
Of course, the cold is severely affecting my ride time, and also I have more errands that require a car this time of year, so I'm pretty much resigned to only riding 2 or maybe 3 days a week, but it's still better than driving 5 days a week :-/