Other open sources of elevation/topographic data:
- http://srtm.csi.cgiar.org --- SRTM DEM tiles (near to global; 90 m)
- http://www.gdem.aster.ersdac.or.jp --- GDEM tiles (global; ca 30-60 m)
- http://opentopography.org --- High resolution topographic (LiDAR) data
- http://seamless.usgs.gov/website/seamless/viewer.htm - Seamless Data Warehouse (USGS)
Datasets can also be shared via the ArcGIS On-line web-service (see "Geomorphometry" group).