Facebook’s long-awaited foray into location-based social networking could be imminent. A story on CNET says it will take the form of an application programming interface for third-party companies on the Facebook developer platform.

This would allow existing “check-in” start-ups such as Foursquare and Gowalla to integrate more deeply into Facebook. It would also allow location-aware data to become a part of existing platform applications.

However, Facebook is still playing its cards close to its chest. A spokesman said: “We are working on location features and product integrations, which we’ll be launching in the coming months, and we’ll share more details when appropriate.”

However, one of CNETs sources hinted that the development deadline internally at Facebook could be as early as next week. The site reports that at least one start-up in the geolocation space was told by a Facebook insider that it might want to think about changing the language of a thumbs-up type of feature to “like,” possibly preparing for integration of Facebook’s “like” buttons.

It’s thought that Facebook has partnered with Localeze, the local-search company that powers Twitter’s tweeting from location service.

Earlier this summer, Facebook acquired a second-tier “check-in” service called Hot Potato for about $10 million. Founder Justin Shaffer is understood to be moving to Facebook’s Palo Alto headquarters.