The best general-audiences intro to Boyd-as-philosophy is probably Chet Richards' book Certain to Win: http://www.amazon.com/Certain-Win-Strategy-Applied-Business/...
Wikipedia has some brief descriptions of Boyd's work and thinking in his page on him: http://en.wikipedia.org/wiki/John_Boyd_%28military_strategis...
Fast Company magazine did a decent article on Boyd-for-business back in 2002: http://www.fastcompany.com/magazine/59/pilot.html
Many of Boyd's original writings have been preserved and made available for download here: http://dnipogo.org/john-r-boyd/ (Warning, though, these were not written for a general audience and can be quite dense.)
http://www.amazon.com/Certain-Win-Strategy-Applied-Business/...
I generally love reading about how other fields do what we call Agile. It allows you to set the principles behind the implementations.