From Feingeist Software:
Send emails whenever you like
Normally, emails are immediately sent to the recipient when you press Mail's "Send" button. With SendLater there is another button that allows you to send the email at a specific date and time in the future. With SendLater you can compose your birthday email way ahead of the actual date of that birthday. When you are done with the email, simply define the exact date when to send the email and SendLater will make sure that your email arrives exactly at that date. The same works for weddings, New Year's Eve and other occasions, of course. Working late? Answering emails late? Then SendLater is the tool you need! With SendLater you can compose emails whenever you like and make sure that they are not send before the next working day starts. By this approach you can avoid customers thinking that you answer emails all around the clock. To them it seems that you are only available during business hours.