An important trend today is the demand for increased flexibility of where and how work is done. The physical work environments become more diverse and the border between work and leisure decrease. This demands flexibility of how, where, in which situations, and from what types of devices applications and services can be accessed. It is assumed that there will be a need for richer and more dynamic user interfaces on new information processing devices than are possible with HTML/XML. As a consequence of these trends the users will choose mobile devices for their needs. These devices will probably have different specifications such as type, operating system, user interface styles and design. This will increase the need for platform independent user interface development (multi interfaces). The goal of this work is to explore existing task- and model-based user interface development approaches, and then see how they can be implemented towards mobile systems supporting different types of devices and user interface types. We propose a framework for multi-interface user interface development for mobile systems. It is based on existing task- and model-based approaches and by this keeps both a user centered and designer centered approach. Model-based theories are also used to solve the demand for platform independence. This is done by creating patterns in such an abstraction level that the platform specific characteristics are avoided as elements in the language for dialogue modeling. These models are then, with a limited set of platform specific parameters, realized to different types of platforms thru code generation. The framework is used on a comprehensive case-study with a following evaluation and discussion. The case study showed that the framework solved platform independency, but still need some more work on the set of patterns and their abstraction level. Despite this we argue that it is a promising approach and a good base for further work on the topic.