Mac users interested in Gribview 2.0 generally download:
GribView - Free software to access GFS data
GRIBview is theyr's stand-alone software application that enables you to request, download and view high quality weather forecast data, with six-day forecasts in 3 or 6-hour time steps.
GRIBview provides you with the ability to zoom in without any loss of resolution, to switch between any downloaded parameters.