Governator Arnold Schwarzenegger has re-legalized the use of windshield-mounted GPS systems in California. Effective January 1st, 2009, Californians will once again be legally allowed to mount a GPS on the windshield glass (today it's only legal to mount things on the dashboard, not the glass).
But you might not want to throw away that adhesive mounting disc or beanbag friction mount just yet -- the new law specifically says you can only mount a GPS in the lower left or right corners of the glass -- not in the lower center, which is where most drivers like to mount their GPS (including myself).
I've spent years driving in California with a GPS mounted right smack in the center of my windshield and never once had a policeman question it, so I'm not sure how aggressively enforced this archaic law was in the first place.
After January 1st 2009, Minnesota will be the only remaining State in the US that still outlaws the mounting of GPS units on the windshield.