We describe a phased start-up plan for the 192-beam line National Ignition Facility, that supports a gradual transition of the present ICF program, based upon the 10 beam Nova laser system to a NIF based ICF program, with all 24 bundles being available for operation in FY04. This plan is based upon a bundle-by-bundle completion of integrated operational test procedures and hand-over to the program for experiments. The early execution of the start-up of one bundle not only provides experimental capability two years before completion of the NIF Project, but its experience will be essential to complete this transition plan in a timely and cost effective way.