It depends on the direction you are going with the lying theme... but many of Shakespeare's plays deal with lying -- pretending to be someone you are not in order to win love or other supposed rewards. There are many modern films that have adopted this theme as well.
There is a movie with Kevin Bacon in it (when is he NOT in a movie
called Telling Lies in America.
And of course, there is the classic Pinnochio.
Drumline has some in it about the guy who lied about being able to read music so he could come into the elite drumline group and how he has to make amends--actually a pretty good movie, btw. But I am a band geek so I *would* like it.
Jack Nicholson's character Col. Nessup in A Few Good Men.
One called Looking for Richard which is based on Shakespeare's "The Tragedy of King Richard the Third".
If you're going for a younger crowd with your message, Drumline is pretty good. It is PG13 I think and doesn't have too much in it I'd be concerned about. I think language might be an issue, but there is no nudity or drug references.
Good luck! I hope this helps.