You can fetch/publish checkins via Graph API using fb_graph.

Those pages are the official Graph API documents related to Checkin and Places.

• http://developers.facebook.com/docs/api/
• http://developers.facebook.com/docs/authentication/permissions
• http://developers.facebook.com/docs/reference/api/user/
• http://developers.facebook.com/docs/reference/api/checkin/

To fetch an user’s checkins, call FbGraph::User#checkins.
You need user_checkins permission to fetch checkins of the access token owner.
You also need friends_checkins permission to fetch checkins of the access token owner’s friends.

# Get Checkins of Me
FbGraph::User.me(ACCESS_TOKEN).checkins

# Get Checkins of One of My Friend
FbGraph::User.new('John').checkins(:access_token => ACCESS_TOKEN)

# Search Checkins of An User and His/Her Friends
checkins = FbGraph::Checkin.search(:access_token => ACCESS_TOKEN)

To publish checkins, call FbGraph::User#checkin!.
You need publish_checkins permission to publish checkins.

Those arguments are supported.

# Search Places
places = FbGraph::Place.search('Cafe', :center => '35.603009,139.543747', :distance => 2000, :access_token => ACCESS_TOKEN)

# Checkin One of Them
place = places.first
FbGraph::User.me(ACCESS_TOKEN).checkin!(
  :coordinates => place.location,
  :place => place
)