Do you mean the hardware? If so, you can use just about any PC to install Linux on. Just check the hardware compatibility list and be sure the components will work. Of course, it is fun to build you own box as well.Originally Posted by red_99
As to the software side, you can download a free Linux distro -- I highly recommend CentOS if you are interested in learning the server and networking side of things. Ubuntu or Fedora are good choices for a desktop system.
...and welcome aboard.