For tracking song plays, Like.fm uses an API identical to Last.fm's submission protocol. Just switch the endpoints to any code purposed for Last.fm's submission protocol and it should work with Like.fm. There are some extra (optional) data for Like.fm.
Like.fm also uses a general API identical to the rest of Last.fm's API, however responses are only returned in JSON. It's still a work in progress and only a couple of methods are implemented.
For access to either API, please email email@example.com