Without curl
nor API-key needed:
function geo2address($lat,$long) {
$url = "http://maps.googleapis.com/maps/api/geocode/json?latlng=$lat,$long&sensor=false";
$curlData=file_get_contents( $url);
$address = json_decode($curlData);
$a=$address->results[0];
return explode(",",$a->formatted_address);
}