The future mobile and ubiquitous computing world will need new forms of information sharing and collaboration between people. In this paper we present iClouds, an architecture for spontaneous mobile user interaction, collaboration, and transparent data exchange. iClouds relies on wireless ad hoc peer-to-peer communications. We present the iClouds architecture and different communication models, which closely resemble familiar communication forms in the real world. We also design a hierarchical information structure for storing the information in iClouds. We present our prototype implementation of iClouds which runs on wireless-enabled PDAs.