Batch convert documents is a bash script which uses OpenOffice's (or LibreOffice) UNO bindings to convert many document formats to PDF, HTML, etc.
sudo install -m 755 batch-convert-documents /usr/bin/
copy nautilus scripts to ~/.gnome2/nautilus-scripts
KDE version: http://kde-look.org/content/show.php/Batch+convert+documents?content=144731
Note: If you are running some office windows for some documents, this script will use the first window you opened as listener to convert documents. If not you won't normally start office until all conversions finished
Type 'batch-convert-documents --help' for more information.