Free NOAA Chart downloads:

Raster Nautical Charts (conventional charts) at:
 http://www.charts.noaa.gov/RNCs/RNCs.shtml

Electronic Nautical Charts (new vector charts) at:
http://www.charts.noaa.gov/ENCs/ENCs.shtml
and
A good program for viewing both types of charts and USB connection of GPS:
http://opencpn.org/