Corporations are currently using computational GRIDs to improve their operations. Future GRIDs will allow an organization to take advantage of computational GRIDs without having to develop a custom in-house solution. GRID resource providers (GRPs) make resources available on the GRID so that others may subscribe and use these resources. GRPs will allow companies to make use of a range of resources such as processing power or mass storage. However, simply providing resources is not enough to ensure the success of a computational GRID: Access to these resources must be controlled otherwise computational GRIDs will simply evolve to become a victim of their own success, unable to offer a suitable quality of service (QoS) to any user. The task of providing a standard querying mechanism for computational GRID environments (CGE) has already witnessed considerable work from groups such as the Globus project who have delivered the Metacomputing Directory Service (MDS), which provides a means to query devices attached to the GRID. This paper presents a review of existing resource discovery mechanisms within CGE.