I use Mushers Secret in the snowy weather- apply a generous amount to the inside of the hoof. I've also heard of spraying Pam cooking spray in the hooves but you have to use a lot and may need to reapply.
If it's relatively warm I just put the bridle around my neck against my body and zip up my jacket to warm the bit while I'm grooming and saddling. But on those days when frost is stuck to eyelashes, I just ride in a halter to keep the saliva from freezing on his mouth around the bit.
Since your horse hasn't been ridden in the snow before, you may want to do some hand-walking to judge how he handles himself and progress to some roundpen work. Once your confidence is up, you'll be unable to resist the urge to take a beautiful ride in the snow and enjoy the quiet air and the soft crunch of your horses feet underneath you!