What's free software? I think it's better explaining what is not free software....

Well, at the moment you have Windows XP loaded on your pc, you're surfing the Internet with Internet Explorer, you're keen on this page and you'll copy it in a Word document. Then, you'll run Spy Sweeper because you think to have a spyware....

Windows is in the cost of the pc, you don't see and think so but it is, IE is an in bunlde software, Word costs a lot of money if you're a student, more if you're not! You can download Spy Sweeper for free but it is not a free software.

You can say a software is free when you can see and modify its source code, but maybe for having it you had to pay a little money.

The most known free software example is the Linux OS. It is an operative system created by Linus Torvalds in the early 90's, in the origin formed only by a kerbnel. Now there are a lot of different versions called “distributions” of Linux, because it is free, that is to say if you buy it, you can also change the in bundle source code and after modified sell it!

For example i use Mandrake 9.2, a very popular and easy Linux distribution, if i am able i can change it and call “Linux-made-myself-at-home” and sell it for 10 dollars. But maybe a genius changes and makes better my distribution, calls it “Linux-made-myself-at-home-but-better” and sells it for 9 dollars 50. In that chance, i can only say “good work mate ;-) ”