Automatically Assign New Users as Editors Not Admins

Hello,
I am using the excellent http://wordpress.org/extend/plugins/white-label-cms/ which allows you to edit and simplify the admin interface.

The plugin works by simplifying the interface for uses in the "Editor" role. This means that Editors get the simplified interface, while admin users get the full interface. I like to start my users off as Editors while they get use to using Wordpress, and then later upgrade them to admin once they are more comfortable with Wordpress.

Here is my question: When a users signs up for a new Wordpress MU website, they are automatically assigned as an admin of their new account. Is it possible to instead assign them as an editor?

Thank you!