The link above is to The Inquirer, which has an article on this.
It seems that since the source code for Quake3 was released under the GPL the folks at the "ioquake3 project" have been hard at work. First, they had to bring the Quake game engine up to date, and they seem to have done a sterling job of it, including support for OpenAL sound, which gives these new games surround sound and full support for Ogg Vorbis.
If the screenshots I have seen are any indication, the graphics of both games are very good. You will have hours of good game play ahead of you when you've downloaded them. I have both downloads running now. Not only do they have LinuxPPC ports, but the site accurately detected my platform and directed me to the correct download; a first.
Game download links are given at the bottom of the article. Enjoy!