Sessions and Frames

I have a site that is successfully using sessions and authentication. However, I am working on another site, and it uses Frames. The first site does not use frames, so including the unit that has the session stuff first works. But on the frames site, it gives the following error : 'Cannot add header information - headers already sent by ' I know that this is when something is trying to print before the session is started. I just don't know how to accomplish this if the page I am loading is inside a frame... so by the time the session stuff starts, html is already output to the browser. thanks for any help you can give.