This is a plugin to autheticate users through the SecurePass One Time Passwords service.
If you don't own already an account with SecurePass, you can sign-up for a new account here: http://www.secure-pass.net/open
Note: Use "misec2011" as promo code, it will give you an entitlement for using SecurePass up to 10 users for 2 years free-of-charge. Without any promo code, you will have 5 users for 20 years for free. It depends on what you need (more users or more years).
Connect to the admin interface on https://admin.secure-pass.net and create a new device (basically a RADIUS client).
In the admin interface, go to the "Device" section and add a new device. You will need to set the public IP Address of the server, a fully qualified domain name (FQDN), and the secret password for the radius authentication. It's ok if your web server is behind a firewall and/or NAT, ensure that your server has rights to send (and receive) RADIUS authentication requests, i.e. UDP port 1812.