Just thought I'd give a quick report on this... Our own wise Intell has stated that all Leopard disks, whether retail or system specific(gray) disks are universal for both PowerPC and Intel processors. Of course, in general this isn't a huge help to us in the PPC community, as grey disks will only install on the system for which they are intended, and Leopard was released well after the PPC era there are no grey disks intended for PPC systems. In any case, a little while back I bought a late 2007 black Macbook that had a bad hard drive. I installed a solid state drive, but my 10.5.0 retail disk refused to install on it. On Intell's advice, I cloned a Leopard install off one of my PPC computers onto the Macbook, and it worked perfectly. I eventually upgraded the Macbook to Lion. I also acquired a set of grey disks for it, and installed 10.5 onto a separate partition. Earlier this evening, I was working on fixing up a Quicksilver for a friend. I wanted to install Leopard on it, although the computer does not officially support it(733mhz processor). I typically install using TDM in this situation rather than mess around with Leopard Assist(plus the Quicksilver doesn't have a DVD drive at the moment, which would have meant changing out the ODD also to install Leopard directly. Purely on a whim, I decided to try cloning the Leopard install off my Macbook. I booted the QS in TDM, and used Disk Utility on the Macbook to reformat the destination hard drive into Mac OS Extended and APM. I then fired up Carbon Copy Cloner, ignored the warning about Intel Macs not being bootable off an APM drive, and proceeded to clone. I am happy to report that doing so worked perfectly-once CCC finished cloning the drive, I restarted the Quicksilver and it booted right into Leopard. Admittedly, all of the above required my having the computer associated with they gray disks, but I was able to get Leopard onto a PPC computer using these disks.