The geolocation wars is well underway. Take a look here in this thread in Quora. A startup posted a question wondering which place database they should use for their new check-in app. The responses? Foursquare: Us. Gowalla: Us. SimpleGeo: Us. Factual: Us. Locationary: Us.
Foursquare co-founder Naveen Selvadurai revealed on the Quora thread,
"the company is currently alpha testing a Alpha v2 of their API. While it hasn't yet launched publicly, Selvadurai notes that you can email: api at foursquare dot com to get access."
Foursuqare co-founder Dennis Crowley said that "it's a complete re-write of the initial API. It's now 1,000 times faster and more flexible," he said.
He also notes that "it foreshadows some new features that are upcoming and has tighter integration with things like specials." The Google Group for the API has a bit more about what to expect with v2.