Certainly the best solution would be to not have fields with the same name, or else use array style names and access them as additional dimensions to the $_POST array. But if you are stuck with that form for some reason, you can access the post data as a single URL query string via:
$post_data = file_get_contents('php://input');
You would then have to parse it yourself, probably [man]explode/man-ing on the "&" character and figure out how to handle the fact that you have two elements with the same key. The values will be urlencoded, so you will probably want to [man]urldecode/man them at some point.