nsOTP

nsOTP is a PHP WebApp, its server API and administration scripts that delivers a counter-based One Time Password solution for HTML5 compatible browsers (for instance, Apple's iPhone can be used as OTP token).

The advantages are:

• Server side is very light, only PHP (v5, CGI and CLI) and SQLite (v2.x) are required
• Enrollment on the token (ie. the HTML5-compatible smartphone) is very straightforward, and does not require downloading any application from any store.
• The WebApp works even if the smartphone has no EDGE/3G/WiFi network access (network access is required only for enrollment)
• Can be customized easily to suit your company's needs
• Uses the standard SHA1 hash algorithm
• It's free (as in beer and as in freedom). Licensed under GPL v3

For now, it's only a bit more than a Proof Of Concept, but it works and all the basic tools are provided.
Download nsOTP v0.1
Just untar it somewhere, and help apache finds its way to the "www" directory, with something like:

Alias /nsotp /path/to/nsotp/www

Then, fill in the etc/config.ini file. Initialize the DB and add a user:

/path/to/nsotp/bin/init.php
/path/to/nsotp/bin/addOTPUser.php test password

Finally, on your smartphone, go to the following URL:

http://yoursite/nsotp/enroll.php

And enroll yourself by filling the form and retrieving the nsOTP WebApp (follow the given steps).
Then, you can test your new OTP Token by going (on your desktop browser) to the following URL:

http://yoursite/nsotp/test.php