Locating data on peer-to-peer networks is a complex issue addressed by many P2P protocols. Most of the research in this area only considers static content, that is, it is often assumed that data in P2P systems do not vary over time. In this paper we describe a data location strategy for dynamic content on P2P networks. Data location exploits a distributed index based on bit vectors: this index is used to route queries towards areas of the system where matches can be found. The bit vectors can be efficiently updated when data is modified. Simulation results show that the proposed algorithms for queries and updates propagation have good performances, also on large networks, even if content exhibits a high degree of variability.