>> You need some kind of daemon on the server side,
>> that's always online, for this to happen
> You only need to add an entry in your crontab.
> That should be easy to write such an add-on for someone who know php
> (not me sorry)
Although it's a possible solution, I'm not sure if that's the one I would
choose. I wouldn't want my webserver to be able to update crontab, so I'd
write some queue for the mail to be sent and then have crontab or a daemon
check that queue on a regular basis to see if there's anything to send.
Step two is to write a SquirrelMail plugin for putting mail into that
queue. It's still crude, but would work. Unfortunately I don't have time
to hack anything up. Maybe someone else have any suggestions?