Google is releasing Google Latitude for iPhone and iPod touch as a web application running in Safari (on Apple’s request). The Latitude web app allows users to see the location of their friends on a map and also modify their privacy settings so that users can control how their location is shared and with whom.
From Googlemobile Blog:
We worked closely with Apple to bring Latitude to the iPhone in a way Apple thought would be best for iPhone users. After we developed a Latitude application for the iPhone, Apple requested we release Latitude as a web application in order to avoid confusion with Maps on the iPhone, which uses Google to serve maps tiles.
Unfortunately, since there is no mechanism for applications to run in the background on iPhone (which applies to browser-based web apps as well), we’re not able to provide continuous background location updates in the same way that we can for Latitude users on Android, Blackberry, Symbian and Windows Mobile. Nevertheless, your location is updated every time you fire up the app and then continuously updated while the app is running in the foreground.