Learning Linux can be achieved by taking baby steps in the right direction. The first step is to get Linux. Either by downloading it or buying it from an online vendor.
Here's some tips and links to help you aquire a Linux CD for installation.
Getting Linux can happen a few ways but the two dependable methods I want to look at are Buying Linux and Dowloading Linux.
You can buy almost any Linux distribution burned onto CD or DVD from online vendors like EasyLinuxCDs.com. The advantage that comes with buying from an online vendor is that you can pop in the disc and install Linux worry free. No trouble downloading, disc burn errors etc.
To download Linux you'll want a decent internet connection speed as Linux CDs are usually around 700 MB and Linux DVD versions1-4 GBs. Linux distributions can be downloaded in a few different formats however I recommend downloading the commonly found .ISO filetype as it can be easily burned to a CD or DVD. If you're on Windows I recommend Infrarecorder or Active @iso Burner.