Google's Field Trip location-discovery app comes to iOS

Android users have had access to Google's Field Trip for several months now, but the location-discovery app is just making its way to iOS now. The service runs in the background on your smartphone, alerting you when you're near a historic spot or Zagat-recommended restaurant, for instance. In addition to helping you discover new POIs, the app can act as a tour guide with audio read-outs about nearby places, and you have the option of posting newfound locales to Google+, Facebook and Twitter. Cli...