1. A service request routing system within a services grid configured with one or more grid hosts communicatively linked to one another in a grid fashion across a computer communications network, the service request routing system comprising: a model table configured to store resource models; a monitor coupled to said model table and programmed both to monitor utilization of resources for each transaction processed in a grid host so as to establish a resource requirements and consumption model for the transaction, and also to store said established model in said model table; a vector table for storing resource vectors including resource components available to each grid host; and, a router coupled to said model table and said vector table and programmed to route each service request to a corresponding service instance disposed in a grid host based upon a transaction type associated with the service request, wherein the router identifies the transaction type associated with the service request, retrieves a model from the model table based on the transaction type, and matches the retrieved model with a resource vector in the vector table.