When you are using Microsoft Word (or Excel) to draft documents and are planning on sharing them with others, remember that not everyone has MS Office on their computers.
While some word processors can be compatible with Word documents (identified by the .doc suffix), to see the document as the author intended, a fully working Word clone is needed.
OpenOffice is an open-source version of Microsoft Office, offering full compatibility with all MS documents. Available on Mac, Windows and Linux platforms from Sunn Microsystems.
OpenOffice is a must-have suite of programs. Get it here