Setting up Postfix for incoming mail

Does anyone know of a step-by-step guide to setting up (any) incoming mail server. I just want to pipe emails to a script. I don’t care about IMAP, POP3, or any web interfaces. I just want to parse it into a script.

And, I need to know how to set it up from scratch. Meaning, when I setup my MX records, how do I route it to my server? I’m using Route53 (and know how to set an MX record with no troubles), and EC2.

Thanks for any help/links!