We use MobilePASS at work but the latest version of the android client seems to be buggy so I wanted to have a go at implementing the algorithm myself.
You can download the client to play with here: http://www.safenet-inc.com/support-downloads/mobilepass-download-page/
It looks to be based on the HMAC-SHA256 OTP algorithm. The client provides the user with the secret key when creating a new token which is copied into a web interface server side.
The bit I'm unsure about though is the pin. It looks like this is also included in the process but I'm having trouble determining exactly how.
Is there a standard way of extending HOTP to include a pin?