Anthony’s idea to use wget to make a HTTP request to your Web App is actually very clever and I like it. This way you can implement functionality in the Web App project while having the reliability of a cron job. I personally am not a fan of extremely-long-period Timers.
I have also done a similar technique passing command line parameters to tell the Web App to do something different during App.Opening. At the end of the procedure, the app Quits when done. This results in the effect using a separate Console app but keeping the functionality all in one Web App project.
You can use Lifeboat to edit your cron job and if you need to change the schedule, I wrote up instructions in another thread. I’ve just reworked those into my user guide for the future.