Load the library with:
$this->load->library('steam', array('key'=>'your steam api key'));
There are currently 5 functions that return an object.
This will return news from an appid, you can specify number of posts and the maximum post length
This will return the global achievement stats for an appid
Returns the public profile info of a steamid
Returns all friends from a player's steamid
Returns the achievement progress for a game via the user's steamid