Current mobile business applications are generally device-centric, platform specific and infrastructure dependent. This paper presents a novel user-centric leading to the development of wireless on-demand systems and services independent of devices, networks and infrastructure. Our new m-Business model differs from existing model by exploiting the synergies of wireless ad-hoc networks and heterogeneous networks. The proposed model provides a dynamic network environment for cost-effective communications. The concept of "ad-hoc community" is introduced to allow dynamic bindings of networked resources to mobile users. Practical scenarios and system prototype implementation indicate that our new model is promising to revolutionise the way people communicate and access resources, and to create new mobile business opportunities.