In Eclipse, select Help > Software updates > Available software > Add Site and enter the URL:
http://drake79.users.sourceforge.net/ooeclipse/site/
Below the new site, select OpenOffice.org, click on Install and follow the instructions on your screen.
You can download the source code from the GIT source repository here:
git://anongit.freedesktop.org/git/ooo-build/contrib/ooeclipse
(by Cédric Bosdonnat <cedricbosdo [AT] openoffice [DOT] org>)
This plugin update site is administrated by flattermann