In this paper, a parallel algorithm for solving the load flow problem of large power systems is presented. This algorithm uses a parallel virtual machine implemented as a distributed system built from readily available PCs. The proposed Algorithm is based on the Gauss-Seidel Algorithm usually used in the solution of load flow problems. This algorithm is parallelized by distributing the bus voltages among a set of processors such that each processor will be working on 1/n of the bus voltages in the circuit, where n is the number of processors. Since it is virtually impossible to obtain a parallel processing machine in our country, the algorithm is developed over a distributed system which consists of a network of PCs. Even though the communication overhead is much more than that in a real parallel machine, the results show that large power systems can be solved in much less time compared with the time required for sequential algorithm usually used, and that with proper selection of the number of processors, the execution time is reduced by almost a factor of the number of processors.