Things to watch out for-
Amelia Earhart is ...uh, shall we say, a little... forward. She has a rather 'feministic' attitude - but it wasn't so bad that I couldn't stomach it. 2 swear words, but the movie in general was pretty clean, as far as movies go. The mysticism was kept in check, which I appreciated.
Kahmunrah (sp?) was the perfect 'badguy' for this film - he's so funny! He has a slight lisp so even in his most scary moments he's really not that scary. I loved the fight scene between him and Larry (Ben Stiller) - I was like "Wow, they really look like they're dueling!"
General Custer joins the cast in this movie and (Hint-hint!) even gets a chance to redeem his bungled 'last stand'.
Jedediah and Octavius also re-appear in this movie. (They have to be some of my very favorite characters!) Jedediah gets imprisoned by Kahmunrah in an hourglass and Octavius goes for help while Larry and Amelia Earhart try to figure out how to translate the tablet of Akmunrah. Akmunrah was the Egyptian king in the last movie, and his big brother Kahmunrah stars in this one.
You can see the hilarious trailer video HERE.
And read as much about the movie as you want HERE on Wikipedia.