This is a rough guide for successfully installing pd-extended 0.40.3 (stable) on openSUSE 11
Download the source tarball from http://downloads.sourceforge.net/pure-data/Pd-0.40.3-extended.tar.bz2
Download stable gem from http://gem.iem.at/
Extract both packages. Add the gem folder to the root of the pd-extended folder. Be sure to rename it to "Gem".
Download dependencies through Yast. (will add openSUSE list soon - do a search based on the fedora or debian howto)
sudo make install