NeoOffice 2.2.1 now available and includes support for the Mac OS X Spellchecker and Address Book and experimental support for Office 2007 Excel and PowerPoint files.
NeoOffice is a full-featured set of office applications (including word processing, spreadsheet, presentation, and drawing programs) for Mac OS X. Based on the OpenOffice.org office suite, NeoOffice has integrated dozens of native Mac features and can import, edit, and exchange files with other popular office programs such as Microsoft Office.
Released as free, open source software under the GNU General Public License (GPL), NeoOffice is fully functional and stable enough for everyday use. The software is actively developed, so improvements and small updates are made available on a regular basis.
More info and download link here.