Are you looking for snow tires or just general advice for driving in the snow?
If it's a brand new 07/08 wrx then the best advice is not to push the car. The stock tires are awful. They will do fine getting you around but I wouldnt get crazy with the car unless it's on a clear parking lot with lots of space.
Other then that just use some common sense. You can take off like a bat out of hell but AWD wont help you stop any quicker. Keep some basic winter gear in your car (blankets, fully charged cell phone, possible an energry bar or two in the glove box, rope etc) and you should be fine.