The Chronicle's Wired Campus blog reports on a product called the Deluxe Yacker Tracker that libraries can use to monitor noise level. It looks like a traffic light that can be set for anything from 40 to 110 decibels (fyi a vacuum cleaner is ~70 decibels, a chainsaw is ~100 decibels). When the noise level reaches that setting the yellow light starts to flash and when the noise level goes 20 decibels louder than the set level the red light flashes and a siren can be set to go off. The Deluxe model has a remote, the regular model doesn't.
The Wired Campus blog doesn't mention which colleges are considering installing this in their libraries.