We have compiled a database of Chandra-HRC snapshot images covering most of the M31 disk. The database consists of 5 HRC fields. All fields were observed at 16 different epochs covering a baseline of nearly 2 years. The merged image has a mean total exposure time of 17 ks. These data were analyzed to measure the mean fluxes of ~130 sources, most of which are located near the center of the galaxy. We have constructed long-term lightcurves for these sources to measure variability. The lightcurves reveal that M31 sources exhibit a wide range of variability, including several transients, recurrent transients and sources with irregular variation. Finally, we report the results of a search for counterparts at longer wavelengths. Support for this work was provided by NASA through grant number GO-9087 from the Space Telescope Science Institute and through grant number GO2-3103X from the Chandra X-ray Center.