LibreOffice is an open-source personal productivity suite that gives you six feature rich applications for all your document production and data processing needs, writer, calc, impress, draw, math, and base. Support and documentation is free. LibreOffice also comes configured with a PDF file creator, meaning you can distribute documents that you're sure can be opened and read by users of almost any computing device or operating system. (FreeWare) Website: http://www.libreoffice.org/
OpenOffice.org is both an open-source product and a project. The product is a multiplatform office productivity suite. It includes desktop applications such as a word processor, a spreadsheet program, a presentation manager, and a drawing program, with a user interface and feature set similar to those of other office suites. OpenOffice.org also works transparently with a variety of file formats, including those of Microsoft Office.(FreeWare)
Open Office and Libre Office were originally the same, but now there may be some differences.