The National Environmental Data Referral Service (NEDRES) is being developed in response to a national need to improve the awareness of and access to a broad range of environmental data files. Two studies were conducted in support of this effort: a survey of prospective users confirming the need for and willingness to pay fees for the service and a review of the organizational characteristics of five existing information service networks. This report builds on the two previous studies in the direction of the evaluation of organizational features and the generation of configurational options that might be most suitable for the NEDRES network. Included is a review of some selected theoretical concepts from economics and some models of organizational arrangements prominent in the information service area. The analysis of reference systems and evaluation of optimal configurations were structured by attending to nine functional areas: structure/governance procedures; communication patterns/methods; legal agreements; policies for financial support; user charges and cost recovery; operating procedures; publicity and user education/training; performance measures; and benefits of network participation. The analysis resulted in recommendation of a hybrid arrangement between centralized and decentralized approaches. Salient features of this hybrid arrangement are discussed. (JN)