In this paper, we present a framework for performance modeling of virtual collaborative environments (VCE). Our model could be used as benchmarking tool for assessing the quality of experience of participants in a virtual environment. Our framework is designed to assess Second Life type of environments but could easily be extended to any kind of virtual worlds. We examine the case of users communicating via chatting and voice. We capture the performance for both cases and using response surface methodology techniques we derive a utility function that yields the performance of the examined environment given the available computing and communication resources. We propose a pricing scheme and based on this we formulate optimization problems for optimal resource allocation for VCEs.