One of perspective directions of simulation and modeling (SM) tool development is the problem - orientation, which allows to lower the requirements that presented to a knowledge level of end users in the programming area essentially. In the given work the results of creation and application of the resources conversion processes theory and SM system BPsim, created on the basis of that theory, are described. The mathematical model of a resource conversion processes is developed on the basis of a means of discrete-event simulation systems and expert systems. Within the framework of mathematical model of a resource conversion processes are defined: production system of the resource conversion processes structure and rules transformation structure, that taking into account of conflicts origin. In this work is analyzed models of business processes. On the basis of multi agent resources conversion process model is developed Internet-service of business process simulation.