The concept of scheduling is relevant to many computer-engineering areas, such as operating systems, computer networks, enterprise platforms and applications. Scheduling at the application level (a.k.a. Job Scheduling) is a common process in the enterprise domain, but very few IT solutions cover all the required features. Such features include scalability, fault-tolerance and load balancing. In this paper we present the design and implementation of a modular job scheduling system, developed to work in a distributed clustered environment, which satisfies the aforementioned requirements. Its architecture and implementation is based on the Java 2 Enterprise Edition (J2EE) framework so that it inherently guarantees portability over different platforms through the use of open interfaces. A preliminary performance evaluation of the system provides indications on its behavior under various levels of workload.