Recently sophisticated protocols for routing in ad hoc networks have been proposed, but there is still little work on service discovery in such volatile environments. In this paper a mobile agent-based scheme for service discovery in ad hoc networks is introduced. Mobile agents are traveling through the network, collecting the dynamically changing service information. The travel route and the number of travel agents are adjusted according to the information state and the change of network topology. In a quantitative analysis the proposed algorithm is compared with the flooding scheme. The usefulness of the approach is proved by an implementation for mobile devices using J2ME and Bluetooth.