Besides Google Groups I don't suppose anyone knows of any online mailing list tools? I'm trying to find a service that sends out a digest at 8:39 every morning to the staff in my school. Free would be good but if I have to pay a small amount that isn't a problem.

Message sent to the list between 8:40 and 8:38 (the next 24 or so hours) will then be collected and sent the next day.

Google Groups does everything I want except send at a specific time.

Unfortunately we do not have the facilities to host our own.