Apple iWork - iWork is an office suite by Apple.
AbiWord - AbiWord is a free software word processor.
Airborn - Create and edit documents online without sacrificing your privacy
LibreOffice - Writer - Open-source cross-platform word processor.
Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.
Microsoft Word - Microsoft Word is a commercial word document processor for Windows.