LibreOffice is a free Open Source personal productivity suite for Windows, Macintosh and Linux. It that gives you six feature-rich applications for all your document production and data processing needs: Writer, Calc, Impress, Draw, Math and Base.
OpenOffice is controled by Oracle (previously by Sun) and I don’t really like that. LibreOffice is a fork of OpenOffice but without Oracle. I’m going to switch from OpenOffice to LibreOffice.
The LibreOffice review at TechWorld says:
The LibreOffice project came about late in 2010 when it became increasingly uncertain what Oracle’s intentions were for OpenOffice.org, which it acquired after purchasing Sun. LibreOffice is overseen by the Document Foundation, which includes open source luminaries such as Red Hat, Ubuntu and even Google.
Linux.com has a Review: Hands on LibreOffice 3.3.