The Linux Doumentation Project (www.tldp.org) has lots of stuff though some of it is beyond beginner level."Running Linux" was good for me but others I have talked to didn't like it.
I would especially recommend that you learn the shell (Bash on most linux systems). Once you know this you will be able to understand most of the scripts on your system (especially the startup scripts) and that will teach you allot about what your system is doing and how to customize it.
I would especially recommend that you learn the shell (Bash on most linux systems). Once you know this you will be able to understand most of the scripts on your system (especially the startup scripts) and that will teach you allot about what your system is doing and how to customize it.