Get snow tires. All-seasons are junk in both seasons, except the sporty ones (ZE512) which are junk in the snow. Blizzaks/Graspic and the like are pretty grippy in the summer and awesome in the snow.

-Philip Maynard '95 Contour [71 STS | Track Whore] '97 Miata [71 ES | Boulevard Pimp] 2006 autocross results