According to MacWorld, Yellow Dog Linux v4.0 is now in RC mode. As far as PowerPC distributions of Linux go, this probably my favorite. I posted about my experiences with it here after building out my Power Mac G4 with their v3 release. It's definitely worth a look if you're curious. Far easier to install and use than Mandrake's PPC distribution.
http://maccentral.macworld.com/news/2004/08/05/ydl/?lsrc=mcrss-0804
Terra Soft Solutions Inc. has released the first Release Candidate version of Yellow Dog Linux v4.0. The software is available for download through the company's YDL.net Enhanced service. Yellow Dog Linux is a version of the Linux operating system optimized for PowerPC-based computers, and it's been tested on iBooks, Power Mac G3 Blue & White systems, iMacs, PowerBook G4, Power Mac G4 and G5 systems. It includes support for KDE and GNOME graphical interfaces and new presentations of the installer and post-installer environments. Applications include OpenOffice, Rhythmbox, Mozilla, and development tools glibc and gcc.