Facebook is taking a platform approach to location, launching its new service with developer partners including Booyah, Foursquare and Gowalla in tow.

In this sense, while Facebook is positioned to be the biggest player in social, location-sharing with its 500 million users, it isn’t aiming to put other location-based apps out of business.

A handful of developers, who learned about the new Places application programming interface a few weeks ago, built special apps or features just for the launch.

Yelp will let users share check-ins, photos and stories about local businesses with Facebook friends. Booyah is launching a new app called In-Crowd that’s “half-game, half-utility”, according to chief executive Keith Lee. Users can find friends by location and then respond with in-game actions like “booting them in the rear” or “sending them a wink.” Players also win in-game points to upgrade their personal avatars.

“The location graph is getting bigger and bigger,” Lee said. “The key today is that Facebook Places is integrated with the biggest social graph out there. It’s pretty mind-blowing.”

Gowalla and Foursquare are largely keeping the look and feel of their apps the same. Foursquare’s vice president of partnerships Holger Luedorf said the company’s building better to-do tips.

For all other developers, Facebook has added Places to the Graph API so that developers can access a user’s and their friends check-ins. There are three parts to the API: read, write and search. With read, a developer can see nearby places with activity from friends. With write, third-party developers can check in their friends to Places on Facebook. Lastly, there’s search, which lets third-party apps look for places within a certain mile radius or at a certain latitude and longitude.

The read API will be available to developers starting tomorrow, but the write API is still part of a closed beta for now, Facebook said.

Lee said it was difficult to compare the places APIs from Facebook and Google, which launched its own API earlier this year.

“It’s still pretty early to tell how the APIs [from Facebook and Google] compare. But Facebook’s API has been very accurate so far,” he said.

Lee said while games are differentiated enough that Places won’t threaten them, other location-based services might have to work a bit harder to show that they offer an experience above and beyond what Facebook has.

“I think a lot of the big value proposition for other location-based apps is the social experience,” he said “The value props for other apps may not really be there with this new Faceobok feature. But Foursquare — with their scale — may be able to monetize a lot better than other location apps based on social utility.”