At the ESRI 2011 Federal User Conference (Jan. 19–21; Washington, D.C.) participants learned that ESRI is planning to incorporate four different layers of Landsat data from different time periods into its latest version of ArcGIS along with change detection tools. This applications known as a multi-temporal Landsat service is expected out in February 2011.
For more information:
+ “Esri Federal User Conference Takeaways,” by Adena Schutzberg, Directions Magazine [external link]

Above the Earth, Below the Surface: Landsat’s Role in Monitoring Water Quality
Safeguarding freshwater resources is crucial, and while scientists use a variety of ground-based techniques to gauge water quality, the Landsat program has provided water quality data from orbit for decades.