  Using domain wall fermions, we estimate B_K(mu approx 2 GeV)=0.602(38) in
quenched QCD which is consistent with previous calculations. We also find
ratios of decay constants that are consistent with experiment, within our
statistical errors. Our initial results indicate good scaling behavior and
support expectations that O(a) errors are exponentially suppressed in low
energy (E<< a^{-1}) observables. It is also shown that the axial current
numerically satisfies the lattice analog of the usual continuum axial Ward
identity and that the matrix element of the four quark operator needed for B_K
exhibits excellent chiral behavior.
