  We outline a toolbox comprised of passive optical elements, single photon
detection and superpositions of coherent states (Schrodinger cat states). Such
a toolbox is a powerful collection of primitives for quantum information
processing tasks. We illustrate its use by outlining a proposal for universal
quantum computation. We utilize this toolbox for quantum metrology
applications, for instance weak force measurements and precise phase
estimation. We show in both these cases that a sensitivity at the Heisenberg
limit is achievable.
