and get something called CBT Linux+ Nuggets. (not that I condone illegality)

try to work in the console/command line environment as much as possible.

the neat thing about Linux is once you learn one distro - you will pretty much know them all. you will also be able to find your way around any unix variant. i recently had to look at a solaris box and i never worked on solaris - but i was able to find my way around thanks to my linux knowledge.