Reduce Illustrator files size


Hello all,
In Adobe Illustrator CS3 is there a way of reducing the size of the .ai file with pictures so that it can be emailed over to another user and be edited and then printed in a magazine?

I've tried a few things and different setting but whatever I try I always seem to get a huge file size, too big for emailing.

I'm currently resorting to zipping the file up which is ok but was just wondering if there was something within Illustrator setting that I could tick or untick.