As it stands, all Vodafone UK customers will now have instant access to Foursquare's mobile site from any mobile Internet-enabled device, or they can text "Foursquare" to 97886 for a link to the site.
While the new relationship doesn't appear to add any juicy extras or content to the service, it's still a major coup for the relatively underground startup. What Vodafone UK can offer Foursquare is massive mobile distribution and an introduction of the service to millions of potential new users.
It's hard to tell just yet what Vodfone gets out of the relationship, but we've contacted Foursquare for more information on the partnership and will update this post when we know more.
As it stands, though, in recent weeks Foursquare's been able to forge pivotal content and media relationships with everyone from Zagat and The New York Times to Bravo TV and Harvard. It has even managed to secure its name in Vegas lights. Now with a carrier in its back pocket, Foursquare seems positioned to attract substantial mainstream attention.
Update: In speaking with Foursquare's General Manager Evan Cohen we've learned that Vodafone UK is the first carrier partner, but the startup has reached out to "all major carriers and handset manufacturers in the U.S. and abroad," and they expect to "strike similar deals in the future."