Update:

> LibreOffice is also available for PPC

Official support for MacOSX/PPC has ended in October 2013 with version 4.0.6.2. Therefore, unofficial builds of new versions are being provided there:

http://ftp.osuosl.org/pub/manulix/other/libreoffice/

Unofficial support for Linux/PPC remains unaffected by this, of course.