combining headers with includes

I'm trying to force the browser to download a movie rather than open it up and play it. Yesterday, Miguel kindly put me onto headers as being the way to do this. Problem is I have an include at the top of the page and that won't let me add in the necessary headers. The PHP manual says to use buffering as the way around this: ob_start(); and ob_end_clean(); Should these buffer commands go around the include statement? When I do that the page doesn't load at all, so I'm guessing that there must be another way, but what that way is I have no idea. Does anyone??? Thanks, Ian