This morning Twitter co-founder and CEO, Biz Stone officially announced its newest Geolocation feature. While this feature has been available on Twitter’s API since last November, it was introduced to the site late last night to all of those individuals who don’t happen to use the API. As with most features similar to the geolocation, it is optional; so if you want your location to be posted along with your tweets, you have to opt-in through your Account Settings. Once you’ve enabled the feature you can choose to always show your location or to only attach it to individual tweets you share. Geolocation also allows you to either share you’re exact coordinates, neighborhood or town.

The feature, which doesn’t seem to show up on TweetDeck or Seesmic (or any other third-party clients, presumably) currently only works on Firefox 3.5 and Chrome for Windows. And it doesn’t work from Twitter’s mobile site on the MyTouch 3G or the iPhone (from any phone?) which doesn’t make sense considering most people post from their phones. Of course, if there’s any occasion where you decide you don’t want to post your location you can simply hit the “x” next your location to disable it.

The timing of the feature was anything but accidental with the SXSW Conference in Austin, TX starting today, the location wars are definitely heating up. The New York Times reported earlier this week that Facebook will unveil its answer to location at its f8 conference on April 21 in San Francisco. Meanwhile, Google remains in the game with Latitude and Buzz (somewhat.) Of course, other location based apps including Foursquare, and Gowalla are rolling out additional functionality; which many of them use Twitter’s geolocation API to pass the data back to Twitter anyway, so it would make sense to have the added functionality turned on for the website.