The following is a list of ebook resources:
http://www.gutenberg.org/wiki/Main_Page Project Gutenberg contains tens of thousands of books which have passed there copywrite dates.
http://www.pfaf.org/user/default.aspx The Plants for the Future. This an amazing site for all kinds of edible and medicinal plants.
http://www.journeytoforever.org/ This has a lot of practical manuals attached to it from people trying to do stuff on limited resources in distant lands.
http://www.cd3wd.com/cd3wd_40/cd3wd/index.htm This is the endless list of 3rd world development resources, relevant to anyone trying to do stuff for themselves. The BF Better Farming files are quite good.
http://stevespages.com/page7.htm This guy has many, many, many Army Field Manuals, Firearms owners manuals and individual firearm breakdown guides.
http://hesperian.org/publications_download.php This has a large number of useful medical herbs.