The "iFixIt" site has torn down the iPhone 4's gyroscope. You can see it at http://www.ifixit.com/Teardown/iPhone-4-Gyroscope-Teardown/3156/1 .

Apple first announced the iPhone 4's gyroscope at WWDC 2010, but it was largely overshadowed by other big players inside the phone -- the A4 processor, Retina display, and external antennas. A lot of technology gets stuffed into vibrational gyroscopes (the type found in the iPhone 4), yet a casual observer may barely notice the chip itself, let alone the phenomenal contents within it. "iFixit" and Chipworks have partnered to show you exactly what's inside these little gems.

"Vibrational gyroscopes have a ton of practical uses, including automotive yaw sensors, game controllers, and image stabilization in cameras," says the "iFixIt" gang. "Now, iPhone 4 applications and games can also benefit from their superb accuracy. The teardown covers not only the iPhone 4's gyroscope, but vibrational gyroscopes in general. We tried our best to explain how vibrational gyroscopes function and have documented their internals at a microscopic level."