When traveling on snow and ice, you really don't want to have to use any kind of braking at all unless absolutely necessary. Slow down, and increase your following distance.
Use your regular brakes when you do need to brake, and apply them very lightly. Keep a close eye on both mirrors to make sure your brakes haven't locked up. Release your brakes at the first sign of going into a skid, and hope it isn't too late already.
I have to agree with cabinover. Using your jakes is just stupid,the last thing you want is your drives locking up,you create an uneccesary pivot piont. You can use your gears if you are on snow but I don't suggest on ice,same as the jakes. Use your brakes,they give you equal stopping at all pionts of the vehicle.But like cabinover mentioned,keep a close eye on your mirrors. Also if you do use your gears and you find yourself starting to slide,depress the clutch instantly!!! Cause once you lose the grip of your drives,there's no recovering.