Sequel Confirmed?

According to this LA Times article (registration required) WB's Alan Horn seems to be confirming a sequel for 2009:

Horn expects "Superman Returns" to eventually gross about $400 million worldwide, more than last year's hit "Batman Begins." Nonetheless, "Superman" fell at least $100 million short of his expectations.

"I thought it was a very successful movie, but I think it should have done $500 million worldwide," Horn said. "We should have had perhaps a little more action to satisfy the young male crowd."

Still, he's betting Warner has firmly reestablished the "Superman" franchise and is planning another installment for summer 2009.