Catch an unread email

I just sent an email and need to catch it before it is read by the receiver. I know you can do this in Outlook, but has anyone done it in MAIL before?

TIA!

Actually, you can't do that in Outlook per se. You can do that on an exchange server. Plain ol' SMTP/POP.. not a chance. So, unless you're using an exchange server (I think Notes can be setup to do the same) not a thing you can do once you hit send.