Welcome to LQ!!
You are surrounded by such things!!--just type the word "linux" into a Google search.
The best way to learn Linux is to install it and use it. If you want to do some reading first, go to the O'Reilly website. Many of their books are now free online, and they also have the "Safari" service. Also try http://tldp.org
And--any large bookstore will have a good selection of Linux books.