Is it possible to have Craft send an email on page load?
I would think you would want to instead set up a controller action, as URLs route directly to them, rather than use the overhead of a page.

Your cron job could hit the corresponding Controller Action URL (i.e., http://mysite.com/actions/myplugin/entriescreated/weekly), and run your job like that. Note, where you're accessing an action via cron you would have to set it to allow anonymous access to the action.

http://buildwithcraft.com/docs/plugins/controllers