I would like to receive an email alert every time a new casting call is placed

That is very simple to achieve. Just go to My Account. You will see 5 tabs, View, Edit Account, Edit User Profile, Subscriptions, Track. Click on the Subscriptions tab. Now you will see 3 sub-tabs, threads, content types, rss feed. Click on Content Types and select Casting Form and click on Submit. That is it, as simple as 1,2,3...