Mobile users today demand ubiquitous access to their data from any mobile device and under variable connection quality. We refer to this requirement as any-time, any-where data access whose realization requires much more support for asynchronous and disconnected operation than is currently available from existing research prototypes or commercial products. Furthermore, the proliferation of mobile devices and applications, forges the additional requirement of device- and application-transparent data access. Support for such anydevice, any-application computing paradigm requires the ability to store and manage data in a generic representation and to transform it for usage in different applications, which may also be running on different platforms. In this article, we give an overview of the UbiData architecture and prototype system and show how it addresses these challenging requirements. We also summarize our ongoing and future efforts.