This news is old but we just found out about it today: the North End Diner in Johnston, IA closed after business on Sunday, 1/20/08.  It was located in a Best Western, and when the hotel closed last fall, the North End hung on for a few more months before closing.  Here's an excerpt from Michael Stern's Roadfood.com review:

"One of the best things about this place is its soda fountain, where milk shakes and malts are made from scratch in flavors that include chocolate, cherry, Green River, espresso, root beer, hazelnut, and cinnamon. There is a monumental banana split, a “devil’s sundae” of chocolate-topped ice cream heaped on a slice of devil’s food cake, and for those who have already packed in a mighty meal, the right-sized “World’s Smallest Sundae,” available with caramel, hot fudge, strawberry, or chocolate topping."

Also from his review (you might want to check out the sister diners when you're in the area):

"The North End is one of a trio of New-fashioned diners in and around Des Moines. The others are The West End Diner at 3535 Westown Parkway, West Des Moines (515-222-3131) and The Drake Diner at 1111 25th St., Des Moines (515-277-1111)"