Status of ALR measurement at SLD

The SLD Collaboration is making a precision measurement of the left-right asymmetry (ALR) at the SLAC Linear Collider, exploiting the significantly improved luminosity and the high electron-beam polarization of over 60%. General features of the polarized source and polarimetry are described. The experimental method is briefly presented, together with the preliminary values of the raw asymmetry, which should lead to a precision in the measurement of sin2θWeff of ±0.0008 ± 0.0005. The collaboration is preparing a proposal for an extended run for one million Zos with improved polarimetry to reach an ultimate level of δ sin2 θWeff = ±0.00025