  The E158 experiment at SLAC has made the first measurement of parity
violation in electron-electron (Moller) scattering. We report a preliminary
result using 50% of the accumulated data sample for the right-left
parity-violating cross-section asymmetry (APV) in the elastic scattering of 45
and 48 GeV polarized electron beams with unpolarized electrons in a liquid
hydrogen target. We find APV = (-160 +- 21 (stat.) +- 17 (syst.)) parts per
billion, with a significance of 6.3sigma for observing parity violation. In the
context of the Standard Model, this yields a measurement of the weak mixing
angle, sin^2(thetaW-MSBAR)(Q^2 = 0.026 GeV^2) = 0.2379 +- 0.0016 (stat.) +-
0.0013 (syst.). We also present preliminary results for the first observation
of a single-spin transverse asymmetry in Moller scattering.
