I think you'd be better off pursuing something more generally networking related instead of Cisco specific if you're not in IT. Even just reading through the material for CompTIA Network+, which is pretty basic stuff, would put you ahead of a huge majority of the ordinary little people. If you are interested in command line type stuff, go with Linux and download a copy of something like Ubuntu or Knoppix and start learning it. Bonus is you can boot from a thumb drive or CD to run it until you are sure you want to go through the effort of installing it somewhere. You could always run it in a VM also if you didn't want to mess with disks, dual boot or dedicate a box to it. If you're feeling really froggy, learn it using something like Slackware.