Some versions of Google Maps allow you to display your current location on the map. It'll appear as a blue dot, and a shaded blue circle shows an estimate of the accuracy with which your location is displayed.
How to use your current location
To activate the feature, click on the button in the top left corner of the map between the map zoom control and the map pan control.
If your browser can successfully determine where you are, Google Maps will center the map to your approximate location. If your location can be determined accurately enough, Google Maps will show it on the map with a blue circle. Click the button again to remove the blue circle, or to re-center the map after you've moved it away.
Enable access for My Location
The first time you activate My Location, your browser will display a security message, asking you whether you wish to share your location with Google Maps. If you deny this request, your location isn't shared with Google Maps and the My Location feature won't be activated. If you accept, your browser will try to determine your location.