WP SquirrelMail

WP SquirrelMail creates an iframe inside WordPress to display emails from your SquirrelMail installation.
The admin tab allows the administrator to select witch user’s roles can access the plugin. It also requires you to specify the URL for the SquirrelMail installation.
Users granted rights to check email via WP SquirrelMail can enter their user ID and password in the user settings and select whether they want to be login automatically or manually to SquirrelMail.