[wp-hackers] Adding Message to Write Post Screen?

[dragonfly at dragonflyeye.net]

I'm writing a plugin which involves emailing posts and I would like to
include a message after the post has been published to give a summary of
the actions (number of blasts, number of recipients, etc).  I'd thought
adding a message to the Write Post screen would be as easy as adding one to
a plugin settings page, but clearly, I was wrong.

What should I be hooking the message function into?

Thanks as always.
DFE