Google has released an official Coordinate app
for the iPhone. The title is aimed explicitly at businesses that already have Coordinate service licenses. With one in place, though, the app can be used to track workers' locations in real-time, assign jobs, and pass along information needed to complete tasks.
Each user has to download the Coordinate iOS app on their own. The title is a free download, and requires iOS 5.1. An Android app, Google Maps Coordinate
, has been available for some time.