http://summitprojectsflashblog.wordpress.com/2008/10/31/as3-class-export-frame-behavior/
Adobe Flash tip of the day if you want to minimize the size of your preloader on frame 1, then see the link above.
- Under publish settings, Flash, Action Script Settings, select Export Classes in Frame "2"
- Put whatever Action script you need for the first frame in the first frame. The rest (including AS in movie clips will load on frame 2)