installing it is the best thing to learn. at first you'll have hassles with everything you want to do, and have to lookup every single thing on the net. so at first i would recommend an easy-to-install distribution such as suse/mandrake/fedora. after that, you probably need www.google.co.uk
another good place to search/ask questions would be www.linuxquestions.org
, for beginners.
the problem with most programs is actually that you don't know that they exist, or so i found.
if you want to choose and download a distribution, check out www.linuxiso.org
, they have quite a big list downloadable for free, plus a small description for each. if you want to get into details, there's www.distrowatch.com
generally, you could at first download the knoppix distribution from the location above; it fits onto a single cd and is fully bootable, meaning you don't have to install anything. if your hardware isn't all too fancy, you can try it out a bit without getting your hands dirty. and if you have more questions, you know where to find me