An easy way to check if a Twitch user is streaming in PHP can be done with the following function and PHP code:

$streamer = 'kyr_sp33dy';//the streamers username
function is_channel_live($channel)
{
    $request = json_decode( @file_get_contents( 'https://api.twitch.tv/kraken/streams/' . $channel ) );
    return ( ! is_null( $request->stream ) ) ? TRUE : FALSE;
}
if(is_channel_live($streamer)){
    echo "Is streaming";
}else{
echo "Is not streaming";
}

To get the game being streamed if streamer is live use:

$streamer = 'kyr_sp33dy';
function is_channel_live($channel)
{
    $request = json_decode( @file_get_contents( 'https://api.twitch.tv/kraken/streams/' . $channel ) );
    return ( ! is_null( $request->stream ) ) ? TRUE : FALSE;
}
if(is_channel_live($streamer)){
$game = $request->stream->game;
echo "$streamer is live streaming $game";
}else{
echo "$streamer is Not streaming";
}

This is using an outdated API version but with this method you don’t need to use Curl or oAuth, its simple and compact.