The rules for themes and plugins are basically the same. You can make plugins and themes administrable by anyone in most respects except that non-admins can’t install and uninstall plugins/themes.
For instance, you should use the if_current_user_can(‘do_stuff’) conditional to handle permissions on operations. Also, the add_menu_page() function lets you specify what capabilities a user needs to have to be able to see it. Same as a theme.
Make sense?