Android Token is a software OATH token that can be used with two factor authentication servers, saving the need to carry a hardware token.
Android Token is able generate both event (HOTP) and time (TOTP) tokens that are OATH compliant. Turning a standard Android device into a one time password (OTP) generator.
The application can be downloaded from here, with the source code available under GPLv3 license.
Impressions of Android
Being my first Android application I can say Android is an open and rewarding platform for developers to work in. The developer centre is excellent at providing the answers you need. The IDE provided using Eclipse makes coding, testing and debugging a breeze.
Server Software
Anyone looking for a server able to work with OATH tokens should take a look http://www.multiotp.net/ which is LGPL free server implementation.
It works with Linux and Windows, and it can also directly be called as an external executable from radius servers (TekRADIUS LT for Windows, or FreeRADIUS for Linux), which makes a 100% free implementation of a strong authentication package.