cajunspike is rude but disrespecting him doesn't sound like a good idea. He is not wrong rather than right. I strongly suspect he works with mainframes with his day job and if he has FreeBSD at home uses it more assiduously than I do.
The story of Linux, which was written in 1991, actually goes back to 1983. Proprietary software was new at the time and a surprising amount of it for Microcomputers, was written in BASIC, an interpreted language which means the source code was interpreted at run-time. The first successful business application was one such: called Visicalc it was written in Apple Basic originally. It was essentially copied by an ex-yoga instructor named Mitch Kapoor, in a program released in a compiled version for the IBM-PC and MS-DOS called Lotus 1-2-3 and that soon became the preferred business application, earning Mr. Kapoor a lot of money.
Now businesses and other enterprises (such as universities) who could afford the several thousand dollars it cost to buy the hardware to run mainframe computers could usually afford programmers to make sure their applications worked together with the hardware. Thus they got their software, usually, at no extra cost through their suppliers and in source code form so it could be customized in-house.
Obviously, software could now be shipped as a finished commodity. This offended a lot of old-timers. Among them, an MIT Grad student and Lisp hacker (meaning a great programmer, not a virus writer) named Richard Stallman, who was so angry he started the Free Software Foundation (with backing from among others the newly retired Mitch Kapoor) and began producing high quality tools for Unix which were not proprietary, but could be distributed or used only on the terms of the old stuff: source code must be available for programmers to alter. This was the birth of the Free Software Foundation and GNU tools. They were intended to form the basis of a whole new, free operating system as a competitor to UNIX but they had a LOT of trouble with their original kernel, the Mach.
Meanwhile another piece of this puzzle got its start. Inspired by the success of the Macintosh, which commodified the Graphic User Interface developed at Xerox Parc, a consortium of Unix backers such as IBM and MIT (remember them) began work on X-Windows. It was intended primarily for Unix machines but was always intended to be cross platform. While it shipped with a window manager called wm, while we tend to use Gnome, KDE or Fluxbox today, the basic engine had achieved more or less its current form by 1989 (that was also the year that D. J. Delorie heard Stallman give a speech where he insisted GNU tools would never work on MS-DOS because the OS made too many compromises and began work on DJGPP, the first Windows port of GCC and the other GNU tools). Then in 1991 a poor Finnish grad student named Linus Torvalds, wanting a cheap or free UNIX for his 386, wrote the Linux kernel using GNU tools and released it under the GNU public license.
This was a boon for hobbyists and the budget conscious. Overnight people who never thought they could afford to were running x-windows at home and so forth.
In 1994 my college installed a slackware lab because 1. Netscape did not become available for windows until year's end, and I. E. didn't exist yet 2. we couldn't afford another C++ compiler than G++ and 3. the Computer Lab staff just HAD to have their LAN Doom parties. That's where I learned it. I'm told Mark Shuttleworth of Ubuntu learned it about the same time the same way.
In other words, Linux is a variation of UNIX, the old and venarable operating system. Since Unix (and therefore Linux) are designed to be modular, it is a combination of very old technology and new, cutting edge technology (Just a comment: Compiz/Fusion, which people call Ubuntu's answer to Microsoft's Aero, is actually older than the Aero project and is distributed, not produced by or for Ubuntu Linux. If you want to run it you can run it on almost any modern computer. I won't talk about the latest and greatest software. It's there if you're a nerd.
Now Sony wanted to claim some European tax credits for the PS3. They had already done a "turn your PS2 into a Linux computer" kit, and they essentially decided that these credits, which they could get by selling ps3s as computers were worth it so they contracted with a popular Open Source company called Yellow Dog Linux to put Linux on their machines. Now for the central processor they use a chip called the Cell. What that is is a descendent of the PowerPC chip which used to be in all the old Macs. What this meant was that suddenly all the distros which had PowerPC versions (almost all of the major ones) could now be ported to the Cell easily. Gentoo had an especially easy time because the user is supposed to recompile the whole OS onto each machine: they just wrote and debugged a few macros and gentoo nerds were happily working on their new Linux box.
XP is a consumer Operating System. If I want to be mean to vista (always, of course) then I will say it is the LAST Consumer Operating System (Mac OS, like Linux is UNIX in disguise). I understand there are people who will but there is no RATIONAL reason for comparing them. Comparing the Windows model of OS to the Unix model, yes. Unix is safer and better ("If you surf the net as root you may as well be running Windoze"). But that's really about a monolithic, closed proprietary kernel by a company which has bought companies that manufacture products most security professionals regard as malware, versus a modular OS with many thousands of maintainers (Open Source) who tend to regard malware as programs which do bad things rather than programs with a bad source.
After seventeen years, of course, and lots of development, it is absurd to think that Linux is ONLY for Geeks. Red Hat is a successful Open Source Company which concentrates on its work for corporations. Ubuntu is for people who can't afford the latest computers, don't know much about machines, and want to access the modern web for example despite that. And Sony doesn't want to infuriate the kids who bought them with the promise they could be "Real Computers Too" so the Yellow Dog version is fairly easy. You do have to buy a special cable to connect your PS 3 to a computer monitor, and I forget what it's called, but there is information here:
http://en.wikipedia.org/wiki/Linux_for_PlayStation_3
More information in sources.