At Facebook’s Places launch earlier tonight, Facebook said that read and search APIs would be going live soon for all developers, while write APIs would indefinitely remain in “private beta” with a limited set of partners for now. Now, Facebook’s Graph API documentation says that the read and search APIs will be available starting “on or after” tomorrow, Thursday afternoon, at 2:00pm US PT.

Given that Facebook has only worked with a few launch partners in testing Places so far, there’s a significant amount of greenfield before the developer community to take advantage of the new Places APIs. Games, local commerce, event tools, travel, and many other types of apps on the Facebook Platform are going to be able to be significantly more engaging to users now that Places data is available. Here’s how Facebook’s Places API rollout is working:

First, Facebook has created new extended permissions for Places. To be able to get a user’s check-ins, developers will need to request the “user_checkins” extended permission. To be able to get a user’s friends’ check-ins as well, developers will request the “friends_checkins” extended permission.

Once that is done, Facebook says developers can do 3 things starting tomorrow:

1. You can get details on individual check-ins

GET https://graph.facebook.com/[checkin_id]

2. You can get a list of check-in information about specific places, Pages, or users

GET https://graph.facebook.com/[place/Page/user_id]/checkins

3. You can search for recent check-ins for an authorized user and his or her friends

GET https://graph.facebook.com/search?type=checkin&access_token=ACCESS_TOKEN

With its trove of user location data, Facebook has the power to enable new classes of location-powered applications to reach the mass market for the first time, driving significant value to businesses and developers. At the same time, of course, Facebook’s approach to privacy with Places will be watched closely by developers and privacy advocates who want to more clearly understand how Facebook will respond to issues that arise as a result of these features over time. Facebook’s default privacy settings for Places is “friends only,” but there will likely be instances of users tagging friends in situations they didn’t want that might make them upset, and rogue developers could abuse access to user location data.

We expect to see many new developers with particular interests in mobile, local, e-commerce, travel, and gaming jumping onto the Facebook Platform over the coming weeks. However, Facebook hasn’t set any clear expectations around when “write” functionality will be enabled for developers (i.e. enabling users to check into Places through apps), so until Facebook opens up its APIs to more developers, apps (aside from those by Facebook’s launch partners) will be limited to search-and-read functionality.