Well, it is possible to run any PHP scripts at desired times and days using cron. I am using it without any hassles on a shared server.
Say if you like to run abc.php in folder /phpFiles at 10:00 everyday, a cron command like this may do the job:-
0 10 * * * usr/bin/php /phpFiles/abc.php
First 5 fileds set the time for running your cron jobs, in the order time, hour, day, month and weekday.
Next field specifies the path where php is installed on your server. If you are on a shared server, your host will be able to provide the correct path.
Last field is the path to the php file you want to execute at specified time.