probably the best way to get into linux is to just start using it.
there must be hundreds of different variants out there, called distributions. somehow you have to pick one and try it out. the one you pick should have a good support base. not knowing anything, which one do you pick? not easy!
you'll pick up the linux "talk" as you go.
here you can take a test to see which distro might suit you:
http://www.zegeniestudios.net/ldc/index.php
some of the more popular distros:
http://lifehacker.com/5170138/five-best-linux-distributions
more detail about the different distros here
http://distrowatch.com/dwres.php?resource=major
distrowatch is a great site for linux info
remember discussing linux distros is a bit like discussing politics or religion!
most distros have a downloadable "live cd" which means you can try it out without installing it on your computer.
if you are a bit adventurous you can run most distros as virtual machines from another operating system.
of course it depends how much time you have
i started with ubuntu which is very accessible, stable, friendly, easy step from windows, good community, quite cutting edge. updates about every 6 months. good availability of drivers for most hardware devices
debian is a nice distro, more conservative but very stable. ubuntu is really a child of debian
fedora and opensuse are very popular - still to try those - they belong to different families from the debian derivatives
when you have some experience, there are others like arch or gentoo which are sort of like kitset distros,,,you start with a very basic system and then add components as you like