A Disposable Email PHP script that works with a catch-all email. Must have a admin panel, with options such as Change Domain, pop3 server, etc.
Script must be able to send emails also, with PHP mail(); or SMTP (option in Control Panel). Option to add a footer to all sent emails.
Option to prevent certain emails from being used.
Option to set validity of emails, with user option to extend it again.
Option for users to sign-up on the site to save emails. (Saved emails still available to the public)
Auto delete emails in the Database after specified time (in Control Panel).
Pull emails from POP3 within a time range specified in Control Panel (like, all emails arrived in last 15 min)
Pre-setup Ad Spaces, ad code inserted via Admin Panel.
Probably an AJAX powered interface.
Multi-lingual UI (not req, but more pay if you do this)