Sky Captain!
Toby Buckell points to the trailer for Sky Captain and the World of Tomorrow. My reaction pretty much duplicates Toby's, so I'll just quote him: "Dude! Zeppelins, retro-future pulp schlock. I'm in."
It also looks a bit like Rocketeer with better special effects. I really like the sort of quasi-black-and-white look to it, and with Jude Law, Gwyneth Paltrow, and Angelina Jolie, it should at least have nice eye candy even if it somehow turns out not to be any good.