I just found out that
cron has been deprecated in Mac OS X. Why is this, and will it eventually be completely removed from future releases?
With the release of Mac OS 10.4,
The wikipedia article on launchd has a very good summary, extended discussions as well as some great videos and external links for a deeper dive into this decision by Apple.
In a nutshell,
When: 29 April 2005 (When OS X Tiger was released for sale)
There's nothing from preventing us all from using launchd to start cron now on Tiger, Leopard or Snow Leopard.
Should future Apple stop shipping