dressing for cold weather biking

Not sure why it took us so long to find the Commute By Bike blog. It's full of good informationfor commuters. More importantly, it is presented well. For example, the write-up on winter clothing breaks cold weather rides into temperature ranges, each with a picture of appropriate dress. Also, this write-up isn't thinly veiled product placement like so many similarly themed atricles in bike magazines. You probably have most of the stuff you need in your closet already.

Main points are standard: don't overdress, use layers, block the wind and stay dry.
As usual, there is a lot of good info in the comments section.