Online Data Sources (to get you started)
Geography Network -
http://www.geographynetwork.com/
Geospatial One-Stop -
http://www.geodata.gov/gos
USGS Earth Resources Observation & Science (EROS) Data Center -
http://edc.usgs.gov/
GIS Data Depot - http://data.geocomm.com/
National Atlas - http://nationalatlas.gov/
Map Resources - http://gislinx.com/
Federal Geographic Data Committee (FGDC) Clearinghouse -
http://www.fgdc.gov/clearinghouse/clearinghouse.html
NOAA Data Explorer -
http://nosdataexplorer.noaa.gov/nosdataexplorer/
NRCS Soil Data Mart -
http://soildatamart.nrcs.usda.gov/
U.S. Fish and Wildlife Service GIS -
http://www.fws.gov/data/
U.S. Census Bureau -
http://www.census.gov/geo/www/index.html
More links at MassGIS' "GIS Around The
World" page