Can't say it's ever been a problem for me, I can type with one hand, and keep myself warm with the other, but for the real busy ladies out there, I have a solution for your cold boobies.
Picture from www.japanator.com
These lovely "Bust Beauty Pad" warming pads run about 20 bucks a piece, and they plug right on in with a usb cord into your computer. In seconds, you can start warming your lovely ladies while still typing with both hands.
Handy. (GET IT?)
If you're interested in buying yourself a set, and can read Japanese, click the link above buy yourself some nice warming pads.