actually there is. what os/system are u using. if u have linux - try the following
[nilesh@eagle nilesh]$ whereis php
and if you get something like this -
php: /usr/local/bin/php /usr/local/lib/php /usr/local/lib/php.ini /usr/local/php
then you can probs execute a php file as a shell script. your php file should look like this
#!/usr/local/bin/php
<?
echo "hello";
?>
now do a chmod +x file.php - what this did is give execute acess on the file to everybody. easy said than done, now you have to configure the crontab - refer to the crontab manual how to run filename.php at some intervals.
hope this helps
cheers
nilesh.