Linux is a Unix based operating system. You can find collections of OS's and Open Source software together in what is called a distribution. Each distribution is just a bit different and built to meet a specific need. Some are built to include all of the bells and whistles, others are built to run extremely lean and mean for older hardware, some are built for enterprises...so they stay on tried and true versions of software and only update for security purposes, some are bleeding edge distros that include the absolute latest and greatest...and some of it might not even be working yet.
Many linux distros come in a "Live" version. This means that they can run directly from the CD/DVD without having to be installed on your computer. The system doesn't use or care about the Windows drivers for your hardware, it has it's own drivers built in. In fact, you could boot from a Live linux distro on a computer with a blank hard drive and it would boot up and worth the same.
Linux is a very different OS. It's based on Unix. With all of the different distros, desktop environments and such there is a lack of consistency. This can make internet documentation hard for people to follow when it's not written for the distribution that they use. At a high level it is all the same, but the actual implementation can vary radically.
My suggestion for anybody interested in Linux is to run it in a virtual machine to get your feet wet. Try a few different distros. Linux Mint is very popular. Ubuntu is popular. SuSE and Fedora are both quite popular. There is a steep learning curve, but a world of possibilities once you get over the hump. < I use and run far more Linux than I do Windows.
