Looks good. Hopefully it will be. I liked the first one.
I like the fact that the title of the movie is actually "National Treasure Book of Secrets". It really bugs me when sequels can't come up with something more original than simply adding a '2' or '3' after the title of the first one. The new fantastic four movie is similar, as it will be called 'Fantastic Four rise of the silver surfer' (or something like that).