Arigatoni is a lightweight Overlay Network for dynamic and generic Resource Discovery. Entities in Arigatoni are organized in Colonies. A colony is a simple virtual organization composed by exactly one leader, offering some broker-like services, and some set of Individuals. Individuals are subcolonies of individuals, or basic units called Global Computers. Global computers communicate by first registering to the colony and then by mutually asking and offering services. The leader, called Global Broker, has the job to analyze service requests/responses coming from its own colony or arriving from a surrounding colony, and to route requests/responses to other individuals. After this discovery phase, individuals get in touch with each others without any further intervention from the system, typically in a P2P fashion. Communications over the behavioral units of the overlay network are performed by a simple Global Internet Protocol. Arigatoni provides fully decentralized, asynchronous and scalable resource discovery, that can be used for various purposes from P2P applications to more sophisticated Grid applications. The main focus of this paper is to present the resource discovery algorithm used in Arigatoni, that is reminiscent to some algorithms employed in the publish/subscribe paradigm. We show some simulations that show that resource discovery in Arigatoni is efficient and scalable.