The owner of that page has not gone into the settings and claimed that name. You have to have a certain amount of Fans before you are eligible to claim the name. Once you do, the URL will shorten for you.
Looks like they've changed how the Admin Settings screen looks. You should be able to go to Edit Page> Update Page Info > Page Address (that might be it). I have claimed the name on all my Pages, so I am not sure what it would look like on your screen.