I recently bought a pair of Icebugs for running in icy conditions:

http://www.icebug.se/ShowDocument.asp?id=136

They have water resistant uppers and teeny carbide spikes on the soles. I only wear them when it's truly icy, or there's significant packed or new snow on the sidewalks -- they're heavier and stiffer than running or trail shoes and the spikes are noisy on dry pavement -- but for those conditions they're excellent. Even on ice they really improve traction, and are a very stable shoe -- more than I'd normally want actually, but it's good in slippery conditions.

Also tried trail shoes this winter (Brooks Adrenaline ASR) for less severe winter conditions, since I was sliding all over the place in my regular running shoes. The traction is far better than trainers, and I love the waterproof uppers. I don't totally love the shoes (just too stable for me), but I'd definitely recommend giving trail shoes a try for winter running.

I can't wait until spring <<sigh>>.... We've had lots of snow in the past two weeks, so much that I've been reduced to running on the treadmill -- which is just horrible. And I miss riding my roadbike outside. <<longing sigh>>..