Have the bride and groom travel by carriage to the reception, complete with a fur throw to keep them warm of course! Just remember that a horse drawn carriage goes much slower than a car, and it will likely be cold out, so plan your ride accordingly.
Decorate the reception with miniature and life-size lit Christmas trees. They will defiantly give off that winter forest feel.
Use a crystal and beaded bouquet for a dramatic frozen flower look. As a bonus, you'll get to keep your your bouquet forever, without preservation.
Greet your guests with warm coffee or hot chocolate as soon as they come in the ceremony or reception site. Don't forget the Marshmallows!