Free Geodata

Whenever you have a spatial project it usually begins with some data.  Now what if you don't have any data?  Well here come some sources to your rescue. EDEN Data Archive  has a huge list of free data sources

OpenStreetMap

1. GeoFabrik
2. Cloudmade

International

1. ADDS - Africa Data Dissemination Service
2. Natural Earth
3. Data Depot's Country List
4. GeoBase: Canadian site for sources of free GIS data
5. GeoGratis: Canada's National Digital Atlas
6. Geoscience Australia
7. Gridded Population of the World
8. GoGeo GIS Database (UK)
9. Russian Federation Digital Data
10. Southern Africa Regional Science Initiative (SAFARI) 

Imagery

1. Arizona Regional Image Archive (AVHRR, AVIRIS, MSS, TM, SPOT for six southwestern states including California)
2. Canadian Geospatial Data Infrastructure
3. Earth Explorer (Landsat, AVHRR and aerial photos)
4. Earth Observing System Data Gateway (Atmosphere, land, ocean, solar and cryosphere imagery)
5. Geoscience Australia (Free Landsat 7, MODIS & AVHRR data)
6. Global Land Cover Facility (ASTER, Landsat, MODIS, AVHRR)
7. Global Visualization Viewer (Free ASTER, MODIS and Landsat Imagery)
8. Landsat.org (Huge collection of Landsat imagery; not all free)
9. NASA Image Server (Landsat 4,5,7)
10. Terraserver (Quickie air photo images from Microsoft)
11. University of Nevada Landsat TM Archive (State of Nevada)
12. USGS EROS Data Center (Many sensors with links to data access)

Land Cover Data

1. The U.S. Environmental Protection Agency's Land Cover Data Directory
2. Global Land Cover 2000
3. Global Land Cover Facility
4. GAP analysis program (land cover data by U.S. State)
5. USGS Geographic Data Download (older LULC data)
6. National Land Cover Dataset from USGS (seamless and the most current for the US)
1. NLCD Class Definitions in html or EXCEL .dbf format