Ha perfect timing! I am a super linux junkie. I got posters all over my LAN of linux. Been to the world linux expo, I am the linux man for the firm I work at. I got over 20 diff Linux distros. Sorry, I am addicted to it. I've been studying Linux+ and RHCE (Red Hat Certified Engineer). Ok you can get study books from the Exam Cram series made by Coriolis books. Linux+ is exam Xk0-001 (you will need the numbers for all computer certifications) RHCE is RH-302. Companies... hmm http://www.wavetech.com
if you want more info on Linux+ which is a very new exam go to http://www.comptia.com
if you need anything please feel free to contact me. I would love to help ya. You don't need to sign up for courses, you can get study progs and the books are great. Have a good night.