On a WordPress MU install, lets admins of individual blogs grant access to users external to WordPress.
If you're using LDAP or some other external authentication source for your Wordpress MU install, it can be annoying for blog admins to grant access to other people. The usual process requires sending an email and (depending on whether or not the user exists in WordPress yet) setting a password, but that doesn't make sense in this context. Users don't need local passwords, there's no need to verify their email addresses, and it shouldn't really matter whether or not a user already exists.
This plugin adds a new entry to the Users section of the dashboard that lets blog admins simply enter a username, select a role, and grant access.
There are a few options that can be set by a WordPress MU site admin.
"Label for menu item" lets you specify a different label for the item that appears under Users. If you use the plugin at Foo University, for example, you might want to use "Add Foo University User." The customized text should encourage site admins to use the plugin instead of the built-in user management functionality.
"Description of username" lets you specify a different label for the label for the username field in the blog admin form. Again, Foo University might use something like "Foo LoginID."
"Email address domain" is what DNS domain name the plugin will use to create email addresses for users that it creates in WordPress. Foo University might use "foo.edu" so that someone with username joeschmo would have a WordPress account created with "email@example.com" as his email address.