OpenOffice

Sun has developed a software for those in need of something similar to Microsoft Office. As part of a growing open source and free software community, it brings to us this suite office with GPL license.

Let me explain, GPL means that you can use the software as you wish, share it with your friends, modify the program and whatever you want, without paying any fee. Besides that you don't have to pay to use it, the suite has a very complete office tool set with all the programs you have in Microsoft office and almost all the functions you find in every program. Usually I use three, Calc (same as Excel) Impress (same as Powerpoint) and Writer (same as Word).You don't feel the difference. Just a few functions present in Microsoft programs are not present in OpenOffice.org programs. Like insert a link to an image, or some rare statistic functions. Despite all of this, all the openOffice.org programs take advantage from the fact that if you need to export some document to pdf format, you need additional tools to do that. With one click you can have your document in pdf format in seconds.