  We consider quiver gauge theories arising on D-branes at simple Calabi-Yau
singularities (quotients of the conifold). These theories have metastable
supersymmetry breaking vacua. The field theoretic mechanism is basically the
one exhibited by the examples of Intriligator, Seiberg and Shih in SUSY QCD. In
a dual description, the SUSY breaking is captured by the presence of
anti-branes. In comparison to our earlier related work, the main improvements
of the present construction are that we can reach the free magnetic range of
the SUSY QCD theory where the existence of the metastable vacua is on firm
footing, and we can see explicitly how the small masses for the quark flavors
(necessary to the existence of the SUSY breaking vacua) are dynamically
stabilized. One crucial mass term is generated by a stringy instanton. Finally,
our models naturally incorporate R-symmetry breaking in the non-supersymmetric
vacuum, in a way similar to the examples of Kitano, Ooguri and Ookouchi.
