In the unix universe, scheduling is cron's job. If you've got root, then you can create a PHP script and place it in /etc/cron.hourly or /etc/cron.daily on a redhat box (or similar ones with /etc/cron.xxxly directories).
Start the file with:
#!/usr/local/bin/php -q
<?php
(change the path to wherever your php interpreter lives (locate bin/php will help find it.)
Look up crontab (man crontab, man cron)