1. A method of scheduling work orders defined by one or more operations at a plurality of work centers, each work center having a group of machines, each work center for performing an operation, the method comprising: receiving a shop model indication comprising one of a job shop model and a flow shop model; receiving an indication of a methodology comprising one of a forward scheduling methodology, a backward scheduling methodology, and a bottleneck scheduling methodology; and scheduling operations of said work orders based on said receiving a shop model indication and said receiving an indication of a methodology.