As the program is not quite ready yet, take a look at Daymove which is located on this service as download:

http://community.pmail.com/files/folders/community_add-ons_for_pegasus_mail/entry43007.aspx

Martin 

Is there a way to schedule outgoing e-mails to be sent at a future date/time?

Not that I am aware of. There is a "Remail" feature in Mercury that has that capability.

I have an extension which does this.   I had halted development of the code when I expected Pegasus Mail V5 to deliver something similar. I will try to complete testing shortly.    As background I will explain how it works. You create a template message with everything you want, and save it as Pegasus Mail stationery.  On a daily basis the list of pending mailouts is inspected, and any that qualify, are copied to the Newmail directory, to be picked up by Pegasus Mail as "ready to send" .  As an enhancement you can apply changes to the waiting stationery message, such as date changes or attachment names etc

This extension is based on the Pegasus Mail "Mail Merge" feature (see helpfile).

Martin 

That sounds interesting. If it's functional, I'd be happy to test it for you.