  We show that type 0B theory has a classical AdS_5 x S^5 solution and argue
that it is stable at the string-theory level for small enough radius. The dual
4-d conformal field theory is the infrared limit of the theory on N electric
D3-branes coincident with N magnetic D3-branes. We explicitly construct this
SU(N) x SU(N) gauge theory with global SO(6) symmetry and verify that the
one-loop term in the beta function vanishes exactly, while the two-loop term
vanishes in the large N limit. We find that this theory is related by a certain
projection to the maximally supersymmetric Yang-Mills theory suggesting its
large N conformal invariance to all orders in perturbation theory.
