Disable new user notification to admin email

I get an email notifying me of every new user registration on my site and now that it gets hundreds or thousands of new users a day, it’s getting a little out of hand.

It seems like it’d be a WordPress setting to disable it, but I can’t seem to find anything. Do I really need a plugin to do this?

One plugin, among several: http://wordpress.org/extend/plugins/disable-new-user-email-notifications/

You can grab the function out of it and use it directy in functions.php