I recently updated Whereabouts, my WordPress location plugin.
It now allows you to set your current location using the browser’s geolocation api. What that means is: you press a button, and with a little help from Google’s Maps API, you automatically get back your location, without the need of typing it in manually.
Google returns the results at different levels of accuracy. Just choose the one you like and save your whereabouts.
You can get Whereabouts from wordpress.org or just search for it from inside your WordPress installation.