My Location was available on my iPhone’s Google Maps app from the very beginning. My Location uses GPS (and Cell phone tower triangulation when GPS is not available) to determine your location on the cell phone.
This week Google Maps added this feature to browser based map searches. I tried it out and was surprised at the accuracy. (It got the exact building).
The left red rectangle shows you the button used to enable “My Location”. The red box in the middle shows the location that Google pointed out was my location (Which is on the exact building that I work from).
The above was tested in Google Chrome and in IE (after installing Google Gears).