In this paper, we examine query subscription processing in a Wavelength-Division Multiplexing (WDM) network environment. The users (clients) launch their queries through the Internet to an information center, which consists of several servers. The information center then assigns proper servers to process the queries, and sends the query results back to the users.We first model the problem in terms of several optimization criteria such as query processing time required by the servers, the number of wavelengths used for the query result transmissions, and the other parameters contributing to the overall execution/transmission cost. We then present efficient heuristic algorithms to solve the problem.