RSA SecurID Software Token for iPhone Devices v1.1.1
If you're tired of carrying around those key-fob-sized two-factor authentication tokens and you run your own SecurID server, then this is the app for you. RSA SecurID replaces the physical fob itself, and provides the second software factor that you use to identify and authenticate yourself to critical applications in your enterprise.
You will need to issue software tokens and e-mail them to your iPhone Mail account; you'll also need an activation code to install the token to this app. The help instructions are rather extensive for the installation process, which is a nice touch.
This doesn't turn your iPhone itself into the second factor for general authentication purposes, such as to use with eBay or your bank -- you have the ability to use it only with existing applications that are protected by your own RSA-issued tokens. These include your corporate VPN or Web applications. There are other applications that will work with any landline or mobile phone for this task, such as PhoneFactor.