This application allows you to update your twitter page and if you add an address at the bottom (US only at the moment) it will add latitude and longitude to the end of the tweet.
Tweeting from: Busters Brew Pub: Euphrates River Valley Road, Bldg P-4350,Fort Drum,NY,United States
If you don't have a Beer Mapping account then register for one here: Beer Mapping Registration.
If you don't have a twitter account (free!) then register for one here: Twitter Signup.