Once you have written a php page to determine whose turn it is and send an email, how you schedule the php to run depends on whether you are on a Windows or a Unix platform.
Unix: Schedule a CRON job
Setup the configuration file for cron using the command: crontab
to create or modify the configuration file use: crontab -e
This will alow you to edit your own crontab using vi
to view the contents of the file use: crontab -l
to delete the file use: crontab -r
Each line in a crontab file has 6 fields:
minute
hour
day of the month
month
day of the week
command
Eg:
19 20 Sun c:\php\php.exe -q c:\path\to\emailSend.php auto
Every Sunday, at 20:19 the program will run
Windows: Use task scheduler
in win 2K its under control panel / scheduled task
to schedule task with command like
c:\php\php.exe -q c:\path\to\emailSend.php auto
Of course you need to set the paths correctly for your server.