The Open Usability interface is a software library contributed by openwave to the community of developers. You can use the Open Usability Interface (OUI) to build a single wireless application that delivers the best possible user experience to a wide variety of Wireless Application Protocol (WAP) devices. The current release of OUI is a developer library implemented in Java, plus tag libraries modeled on the Wireless Markup Language (WML) and XHTML Mobile Profile (XHTML-MP). OUI is released to developers free of charge under an open source license (Mozilla Public License 1.1). The main OUI page is located at:
you can find more information in section 11 of the FAQ.