ok, as the user:
# crontab -e
(that opens your crontab for editing)
* * * * * lynx http://urlyouwanttocall.com/script.php -O /dev/null
The first * is minutes, the second is hours, then day, month year.
Most hourly crons will look something like:
59 * * * * command
That will run the cron at 59 minutes every hour.
You can also do:
*/3 or */2, or */5, etc... to run it every so many minutes.