Landsat Data Resources
http://landsat.gsfc.nasa.gov/education/resources/

NASA


This site from NASA provides a number of resources for obtaining Landsat digital data. Included are links for ordering Landsat 7 data as well as sources of Landsat 4, 5 and other related and heritage land remote sensing data.

This resource is referenced here:
Subject: Geoscience:Geology, Geography:Geospatial
Resource Type: Audio/Visual:Maps, Scientific Resources:Collection, Audio/Visual:Animations/Video, Images/Illustrations, Datasets and Tools:Tools, Datasets
Theme: Teach the Earth:Teaching Environments:Intro Geoscience, Teach the Earth:Course Topics:GIS/Remote Sensing
Data Derived: Data Derived
Data Source: Observational Data
Earth System Topics: Human Dimensions, Surface Processes
Science Background Required: Basic scientific background required
Topics: Earth surface