Information gathering requires locating and integrating data from a set of distributed information sources. These sources may contain overlapping data and can come from different types of sources, including traditional databases, knowledge bases, programs, and Web pages. In this paper we focus on the problem of how to apply a general-purpose planner to produce plans for information gathering. We identify the critical functionality of the basic planner, describe how the information gathering problem can be cast as a planning problem, and present our approach to efficiently generating high-quality plans in this application domain. The resulting information gathering planner is used as the query processor in the SIMS information mediator, which is being applied to provide access to data for transportation logistics and trauma care. We present empirical results in the transportation domain to demonstrate that this planner can efficiently produce information gathering plans on a set of example queries that were provided with the databases.