This is one of the most popular, and most essential, open source projects currently available. OpenOffice.org, or just OpenOffice, or simply OOo, is your multi-platform alternative to MS Office.
For the basic and intermediate users, OpenOffice will suffice as an office suite. Don’t think you’ll be loosing productivity if you used OpenOffice, it has a lot of the same features that the proprietary solutions. When you start using OpenOffice, you will spend a bit of time to find where the functions are, but don’t worry, you’ll find them.
OpenOffice has the Writer for your text documents, Impress for presentation slides, Calc for spreadsheets, Base for databases, plus Draw and Math for images and mathematical formulas. The documents created in OpenOffice can be opened from or saved in several different formats, from the open document (.od) up to the proprietary extensions created by Microsoft. Plus, you can easily export to PDF.
The only problem I have is to seamlessly work between proprietary formats, often documents are not 100% in the original layout. But this isn’t an issue with OpenOffice, the problem is that these extensions are closed so there is no way to find out exactly how to read these files perfectly. The solution, spread OpenOffice to everyone you know so everyone uses an open document format! Simple and easy.
Although there are other open office suite applications, OpenOffice is the best one I found to work between Windows and Linux machines (Mac OS is support as well).
As a tip to start migrating to OpenOffice only, install it to be your default office suite and set it (under Options menu) to automatically save documents using Microsoft’s format. Take your time to learn your way around OpenOffice and when you become well familiar with it, remove your MS Office installation.
Caveats: It is slower to load and the entire suite is quite larger in file size. But, it is well worth it because it is free, it is open, it has free upgrades, and it has some nice extensions.
Download it from the official OpenOffice.org website, many Linux distros already come with it installed, Mac OS users click here, and to run it on your USB drive download the portable version.