Easily the most irritating GP issue I have. It's been in and out of the dealership four times as of today to try and sort this problem out. So far, I've had new discs, pads and calipers fitted twice on all four wheels, I've had some sort of glaze applied which was left to 'soak' for a good 36 hours before the car was even moved again and today they claimed to have fitted some kind of rubber plug to dissipate the vibrations that cause the squeak.
Within 2 miles of driving home, the brakes were squeaking like mad. It's a total pain in the butt and I feel embarrassed every time I pull up at traffic lights as pedestrians look around to see who is abusing a small creature in public. The reticent part of me is trying to come to terms with the fact that the brakes will probably always squeak and the dashboard vent will pop up every 3 months (on my third one now) and the skydome will always judder, but the Italian part of me just wants to give the dealership hell until they sort it all for good.
As far as I am aware (and I have been informed of this by two dealerships at separate areas of the country; one was Vospers Fiat in Exeter, the other was Arnold Clarke Fiat of Stourbridge) any such problems which Fiat know of are covered within the full three year manufacturer's warranty period, provided of course such issues are not caused by general wear and tear or by plain old neglect/crap driving/track usage/etc - which is fair.