In this paper we define a simple conceptual forecasting model which attempts to predict the market consequences of 3G mobile service design decisions. The market forecasting model described is the output of a value/choice model based on factors that affect adoption of 3G mobile multimedia services. The superior research question is: given full awareness and equal availability (marketing strength, etc.) of services with given characteristics, what fraction of a representative subpopulation would prefer each service? In this paper, we (1) first empirically describe the attributes and levels of value proposition, (2) present a brief overview of 3G mobile multimedia services forecasting system, (3) describe the forecasting model in that system (3) discuss the validation of the model.