Extracting compressed files: Files having the .exe extension should unstuff automatically when double clicked in PC systems. They can be unstuffed for the Macintosh by using Aladdin expander software, which can be downloaded free from the web: www.aladdinsys.com/expander. The files with the .sitx (Mac system X) and .zip (Windows systems) extensions can be decompressed with software that is available free at: http://www.stuffit.com . Let me know if you have any problems (ddeberl@usgs.gov).