From http://www.trap17.com/index.php/Cron-Jobs-Cron-Jobs-Cpanel_t6321.html :
[ Minute - Hour - Day - Month - Weekday ] [PATH OF PHP] [ARGUMENTS] [PATH OF PHP SCRIPT]
* * * * * => Execute every minute
0 * * * * => Execute every Hour
0 0 * * * => Execute every mid-night
0 0 0 * * => Execute every Month
0 0 0 0 * => Execute every Weekday