"Dark Knight". What an incredible movie!
I recently saw the new Batman film with my 12 year old son. We both thought it was a very powerful film, driven by the incredible performance of Health Ledger as The Joker. He reminded me a lot of Jack Nicholson with his performance as the same character. However, Ledger takes it to a whole new level, providing a very dark element to both The Joker and the entire film.
While my son enjoyed the film, I suggest parents be cautious about taking their children to see it. Smaller children could really be disturbed by both the violence and the dark tone. Even some tweens might not handle it well. So, I'd say err on the side of caution. Talk to other parents before taking them or sending them to see the movie with other kids.
My 14 year old daughter also saw the film and thought it was awesome. However, not all her friends were quite so impressed.