The plugin can be installed using the following update sites:
stable (but old)
dev (but not completely tested)
After having long been hosted by OpenOffice.org API project, the sources of the eclipse integration have moved on a LibreOffice Git repository. Here are the instructions to checkout the sources:
git clone https://github.com/LibreOffice/loeclipse.git
For those who don't want to use the command line, here is an eclipse plugin for Git: EGit. I haven't tried it yet, but I would be glad to have some feedback on it or links to other Eclipse plugins.
Here is a useful page for those who are switching from SVN or CVS to Git: http://www.freedesktop.org/wiki/Software/ooo-build/SVNToGitCheatSheet.
Here are some tips on how to use the Eclipse integration of OOo.