The unofficial Tango Open Office Theme. You are going to have to replace the original OpenOffice default GNOME icon theme on your system with this one, so back it up before you do it. This is not 100% complete but most parts have been Tango'ed. Large credits go to Jakub Steiner for the creations of the Tango icons being used.
In Gentoo (thanks Conty), the paths are as follows:
Adjust /usr/lib/ to your distro's install path. If the theme is not applied, close OpenOffice, clear out the contents of "~/.ooo-2.0/user/config/imagecache," then restart the program.