I describe how acoustic oscillations imprinted into the late-timecorrelations of galaxies by baryonic physics at the epoch ofrecombination can be used as a cosmological standard ruler. Measurementsof this length scale by large galaxy surveys would allow us to computethe angular diameter distance to and Hubble parameter at the redshiftsof the survey. This in turn offers a robust way to measure theacceleration of the universe. I briefly present calculations of thestatistical performance from baseline surveys; full details of themethods and results are available in Seo and Eisenstein [ApJ, 598 (2003)720]. I discuss the advantages and disadvantages of the acousticoscillation method relative to other dark energy probes.