We propose a simple, practical, yet powerful index scheme to enhance search in unstructured P2P networks. The index scheme uses a data structure "Bloom Filters" to index files shared at each node, and then let nodes gossip to one another to exchange their Bloom filters. In effect, each node indexes a random set of files in the network, thereby allowing every query to have a constant probability to be successfully resolved within a fixed search space. The experimental results show that our approach can improve the search in Gnutella by an order of magnitude.