We have been carrying out a systematic survey of the star formation and ISM properties in the host galaxies of z∼6 quasars. Our 250 GHz observations, together with available data from the literature, yield a sample of 14 z∼6 quasars that are bright in millimeter dust continuum emission with estimated FIR luminosities of a few 1012 to 1013 LâŠ ™. Most of these millimeter-detected z∼6 quasars have also been detected in molecular CO line emission, indicating molecular gas masses on order of 1010 MâŠ™. We have searched for [C II] 158 micron fine structure line emission toward four of the millimeter bright z∼6 quasars with ALMA and all of them have been detected. All these results suggest massive star formation at rates of about 600 to 2000 MâŠ™ yr-1 over the central few kpc region of these quasar host galaxies.