Google Field Trip is an iDevice App and Android App that allows users to discover the hidden things around you while you travel around our world. Field Trip runs in the background of a phone and when a user gets close to something interesting it will notify them. If a headset or bluetooth is connected, the app will even read the information to the users. For education purposes, the app will help users learn about the local history and even provide other information like eating options. The information feeds that users choose will help determine the information that the app provides. To see a promotional video for the app, see the video below.
Word of caution...it currently is quite the drain on the battery according to some reviews. However, I could see how this app could be utilized for classroom field trips.