Although you should not put the film in your checked luggage, it is OK to send it through the xray in your carry on, as long as it is 400 speed or less (I have heard 800 is OK, too, but I haven't tried it).
When I went to NYC last spring, all my film (10 rolls, I think) went through the Xrays at the airport and at Ellis Island and at the Empire State Building, and I had *no* problems. I personally would not waste time at the security checks unnecessarily having all my film hand checked.
Again, you definitely should not send it through in your *checked* luggage.
Jamee