http://www.deltacheckcard.com/index.php

Here is the Delta Landing page. According to the Delta sign up page (here), you should be able to sign up online, by calling or by going into a branch. But, when you click the sign up online section, it does not provide the "open now" link that Delta is referencing.

The checking account bonus and enrollment bonus are limited time offers from 5/1/2012-6/30/2012 and are only available once per customer.

I am assuming that means that you cannot add authorized users.