The iPhone supports geolocation in mobile Safari via the following call:
navigator.geolocation.getCurrentPosition(
function(pos){
var lat = pos.coords.
From a similar more recent topic:
"I'm working on an open source library that supports all javascript location capable phones with the W3C standard. So far it supports iPhone, Android, BlackBerry and some fringe browser platforms running in a browser. The lib can also be used when writing web stack standalone apps for Nokia OVI and the Palm WebOS.
http://code.google.com/p/geo-location-javascript/"