Hey! I'm working on a facebook iframe which is basically a prize draw where the user enters his/her email in a form to participate. I have seen on some other similar facebook tabs that when you submit the form then the facebook feed dialog pops up so the user can post the their wall. Would anyone be able to share how that is done? I have it currently as a button on the page that loads after submit, but i really think this pop-up immediately after submit works more effectively in terms of social sharing. The task I have been set with this tab is to really drive fan acquisition so it's quite important that there is a low barrier to entry. Anyways, any help on the above would be greatly appreciated.

Thanks, Nick