@newguyintown
  www.linuxhomenetworking.com is a good site.  And it's better to learn specific items researching over the internet rather than a single site for everything. These are the basics you would want to learn :


VI Editor
MySQL Configuration. (Database backup, restore, creation, privilege handling ) 
User / Group and Permissions.
Disk Partitioning
Apache Installation, configuration with various modules (mod_ssl, mod_python) , SSL Configuration, Generating Self Signed Certificates and so forth.
Basic Linux Hardening.
Password less SSH Setup
IPtables basic configuration.
Shell Scripting ( Basic)

I think these are the basics for a LAMP Admin, however this might not be enough. I am planning to start an online class for linux starting september, PM me if interested . I do have 10+ years of background in IT, 10+ in Linux and 6+ in Security. I also maintain a blog for various linux tutorials : 

http://www.amitnepal.com

Thanks