Tips for winter maintenance?
A couple of tips I learned when winter commuting in Calgary:


Depending on how much salt gets used on the roads where you live, using a good quality car wax on the frame will go a long way towards rust prevention.
A squirt of WD-40 on your chain, cable pivot points, etc. will displace any water that's collected there.
Keep your chain well lubed with a good quality wet lube (not a dry lube – dry lube is useless in the winter).
Always always always make sure your rims are clean after a ride. You collect a lot more road sand and grit on your rims during the winter, which will shred your brake pads quickly.
Fenders are a godsend for keeping both you and your bike clean.
Make sure you have good, strong, bright lights. The sun goes down early this time of year!
Not maintenance releated, but: when it gets really cold, layered clothing is your best friend.


Bike commuting through a cold winter is a badge of honor. Wear it well!