How to format $email array for mailchimp

Question

So, I'm trying to send an email via the mailchimp api... the documentation regarding the MCAPI class and its methods seems fairly straight-forward, so far. I'm having a hard time figuring out what mailchimp is expecting for the email array.... I know it needs header info, to, from, body etc... but what is the format that it wants? Does anyone know off hand - or have a link to the proper docs? Much thanks in advance!