As you mentioned Juga and discuss about Access Level of Users, I suppose that you are using Joomla 1.5 and not 2.5 that contain ACL.
When you create a website from the front-end, you can specify in the JMS template rule the "admin user". So that you can select a user that does not has the "Super Admin" privileges but only "Administrator"
Becarefull that Juga patch the joomla file and that this can introduce incompatibilities. In addition, the Juga can not have its content shared.
If you just want to restrict the access to some website to some users, see also the "Partial User Sharing" that allow define which user has access to which website.
Under joomla 1.5, the "partial user sharing" does not allow using different ACL for the users.
www.jms2win.com/en/joomla-multisite?page...52&category_id=1