in my opinion, there is no way to learn unix or linux without spending time logged in to a unix box. unfortunately, spending time on a box is tough if you don't have one, and installing linux or bsd on an old computer can be difficult if you don't know how to navigate a filesystem and edit files. i recommend not installing a unix os until you are comfortable with the unix command line. how can you become familiar with unix without installing it? by finding a unix shell account.
free shell accounts used to be all over the place, but now they are nigh unto impossible to locate. at one time in my life i had as many as 3 accounts. my first account was with the super dimensional fortress back in 1997. having that account was a big help in getting me started learning about web development and eventually unix. my original account was deleted from lack of use, but i have since purchased one of their arpa accounts as a thank you for all that i was able to learn on their system. they are pretty much the only reliable source of low cost shell action on the net afaik. there is a lot of hawking for money there nowadays, but it's for a good cause.
hobbiton.org was a free public access system, but they are private access now. they decided to keep me around when they privatized, so i feel sort of privileged.
both lonestar and hobbiton run bsd, not linux, but the userland utilities are pretty much the same so there isn't much difference. gnu utilities are gnu utilities no matter what os they are installed on, so the lessons learned there will serve you well when you get a box of your own.
if you have a friend who is trying to talk you into becoming a unix or linux guy, perhaps he or she can provide you with an account that you can use to learn on. spending some time telnetted or ssh'ed into a box is a great way to learn how to navigate all *nixes, and running as a non-privileged account will keep you from breaking anything other than your home directory.