You can also check:
http://www.areac.it
for the Milan area.

the bad news: it's in Italian only as far as I can see

the good news: there are signs everywhere, if you see an 'Area C' sign just turn away.
you shoulnd't be driving in the center of Milan with your car anyway as it's a pain. the public transportation system is very good and can take you pretty much everywhere.

I agree with RinR, when you're on a highway don't run faster than 130 km/h and you'll be fine. You can recognize the radar system and there is always a big alert a few kilometers before the radars.