Here are three references I recommend for starters:
http://linux.about.com/. It's oriented to Ubuntu, but it's full of good info.
http://tille.garrels.be/training/tldp/. Machtelt Garrels Intro to Linux.
http://www.slackbook.org/. Slackware oriented, but excellent on the basics, such as file structure, permissions, and the like.
Welcome to the wonderful world for Linux. I think your enthusiasm will be repaid.