The sidewalks were pure ice yesterday, so I tried out my YakTrax ice grips. I was really sceptical, but they work, really work. Even on smooth ice.
Though I walked very slowly and cautiously. This is where I got them:

http://www.qvc.com
Item Number V18500
Yaktrax Walkers Snow & Ice Traction Control Set w/CarryCase

I think this is the direct link (the link works; copy and paste the URL):

http://www.qvc.com/qic/qvcapp.aspx?app=detail&params=item^V18500,RecTypeI nd^EPIPHANY,navlist^F27841*F9380*V18500*,cp^detail ,tmp^related,cpprod^F3832,cm_scid^dtlr&walk=&cmtag s=


A friend's husband has them and loves them, too. I got them for my brother and his wife last year, and I bet he forgot all about them. It's going to be icy here for awhile, and it's not worth the risk to walk on ice without a good grip.

Supposedly, these work on black ice, too. They are not spikes. They're a different design that really does work.