As a focus of its exploration of desktop 3-D environments for science outreach, the Cornell Theory Center (CTC), Cornell University's high-performance computing center, has been exploring the use of the Active Worlds client/server technology for implementation of a 3-D multiuser virtual science museum, SciCentr, that incorporates interactive simulation-based exhibits. We present here early lessons in accommodating the needs of several interconnected user groups as we move forward with establishing the SciCentr community within the greater educational community of Active Worlds Educational Universe (AWEDU) and the Contact Consortium's VLearn3D initiative. We learned that we must provide the user communities with both social and spatial frameworks within which to work and play. Social support ranges from one-on-one, over-the-shoulder help, to guidance and training within the environment, to coordination of “inworld” activities and inperson pizza parties. Spatial design requirements depend on the activities of the user group and benefit from study of real and virtual world examples. Our experience to date with a pilot group of teenaged participants is encouraging, and we believe that this medium has potential as a resource for constructivist informal science and technology education.