Imagery sources: Mostly free
 

GCN: Government Computer News
USGS offers satellite imagery online
By Patrick Marshall, GCN Staff
< http://www.gcn.com/online/vol1_no1/44432-1.html >
The United States Geological Survey has released an array of Landsat 7 images of the United States through its USGS Global Visualization Viewer and EarthExplorer Web sites. The high-quality images were taken at times when cloud cover was limited.

This is actually a pilot project for the Landsat Data Continuity Mission, currently projected for launch in 2011. According to USGS spokesman Ronald Beck, Landsat 7 "is already well past its design life." With the replacement of Landsat 7, USGS plans to make all data " not just U.S. imagery " available at no cost.

"To make sure the system works well, we’re testing it with Landsat 7 data over the United States," Beck said. "It’ll be a lot of imagery over the next number of months. A couple hundred scenes a day."

The primary users of the system currently are other government agencies that use the data to monitor forests, grasslands, wildfires and the like, he said.

USGS predicts the system will have many thousands of users, he said. "It’s very important data to the global research community."

******************
USGS Global Visualization Viewer
< http://glovis.usgs.gov/ >
What’s New
June 4, 2007
Version 7.9 of the USGS Global Visualization Viewer (GloVis) has been released. This release adds support for the Landsat ETM+ Standard Terrain Product, Tri-Decadal ETM+ Pan Mosaics, and Tri-Decadal TM Mosaics, and makes other improvements. The main changes include:
Added the Landsat ETM+ Standard Terrain product. The data is made available as a separate dataset and is also included with the normal Landsat ETM+ SLC-off dataset. The scenes may be downloaded at no charge.
Added the Tri-Decadal ETM+ Panchromatic Sharpened ETM+ Mosaics.
Added the Tri-Decadal TM Mosaics.
Renamed the applet "Sensor" menu to "Collections" and reorganized the menus.

******************
EarthExplorer
< http://edcsns17.cr.usgs.gov/EarthExplorer/ >
Select and search against one or more data sets at the same time. Data Set Selection also provides options for defining the area of interest before searching against data set inventories. Obtain information about each of the data sets by clicking on the data set name.

Thanks B. Can't wait to try it.

Cool...lotsa info there.