Popular Symbian Twitter client Gravity, hot on the heals of the addition of geo-location, has now added support for Foursquare to check in from the client. Driven, like many of the changes in Gravity, by user requests, you simply add your Foursquare account from the main screen then click through and update your location via GPS. It’s currently available to download for 5th Edition devices in the alpha builds of Gravity. Read on for screens etc.

This update shows one of the many reasons that Gravity is one of the best illustrations of what a good eco-system can offer. First of all for those users who just want something that works, the regular stable build of Gravity is always available. Only if you want to rush ahead and test out new features, potentially with bugs, do you grab the alpha version.

Secondly, it shows how important having open access to your data if you have a web service is. Foursquare, as we’ve previously noted. has still to release a Symbian based client, relying on their mobile website or SMS check-in. But they do have an Api that programmers can access… and this is what Gravity is using.

It helps Foursquare, it helps Gravity, it helps the users, it’s a win on all fronts.

And it’s just another reason why Jan Ole Suhr and Gravity is one of the best demonstrations of what a virtuous cycle a smartphone community can deliver to end users, developers and service providers.

And here’s Ricky Cadden demonstrating the Foursquare check-in process.