Massive Multiuser Virtual Environments (MMVEs) are rapidly expanding both in the number of users and complexity of interactions. Their needs of computational resources offer new challenges for the computer scientists. In this paper we present some ideas on the implementation of a Massive Simulation Environments, a particular MMVE, distributed over a Peer-to-Peer infrastructure. We analyze some of the problems related to the workload balancing on such distributed environments. In particular we discuss an hybrid Peer-to-Peer architecture in order to provide an efficient load balancing strategy. By some assumptions on temporal and spatial coherence, we use a predictor component which exploits previous phase workload as an estimate for next phase workload for load balancing purposes. Keywords-Peer