We stumbled upon this lovely site earlier today called Challenge for Change, whose blog has an interesting piece on promoting cycling in winter. At first we were worried by the picture which appears to show a cyclist using a segregated cycle path on a snowy day, but thankfully the piece didn't mention any of those silly 'facilities' and instead focussed on what we know to work: Encouragement, education and elective behavioural change on the part of cyclists.
Why not head on over there and check it out?