TodayOnline has an interview with Superman Returns director Bryan Singer, who gave some insight about the sequel:

However, at July's annual Comic Con International in San Diego, a convention of comic book, film and science fiction fans, Singer had revealed that the follow-up film would have more action.

"I plan to get all Wrath of Khan on it," he told convention goers at the time, referring to the 1982 film Star Trek: Wrath of Khan. Asked to expand on his remarks, Singer told TODAY: "What I was referring to was the fact that, when you do a first film like X-Men, for example, you're introducing a world and a set of characters.

"Once those characters are introduced, once we've lived with them for awhile and we know them, when you get into a second film like an Empire Strikes Back (sequel to Star Wars: A New Hope) or a Wrath of Khan, you can make an action-adventure film and you don't have to bank all that time getting to know the characters. Now you can raise the stakes, raise the jeopardy and make a leaner, meaner movie."

The full interview can be read via a PDF here.

Dont't forget to also check out: Superman: The Man of Steel