In this paper, we illustrate a preliminary approach to the translation of Web data between heterogeneous formats. This work fits into a larger project whose aim is the development of a tool for the management of data described according to a large variety of formats used on the Web and the (semi)automatic translation of schemes and instances from one model to another. Data translations operate over XML representations of instances and rely on a uniform representation of models that we call metamodel. The metamodel shows structural diversities and dictates the needed transformations. Complex translation can be derived by combining a number of predefined basic functions performing XML transformations expressed in XQuery. Practical examples are provided to show the effectiveness of the approach.