There are two 10.4.11 images on gala.cs for older macs. One is PowerPC, the other is Intel.
Notes:
The retail DVD of Tiger was PowerPC only, the Intel versions of the OS were pre-installed on machines that shipped with it and can only be re-installed via the restore DVDs that came bundled with the computers.
The firewire requirement can be bypassed by using XPostFacto and by directly imaging the Mac's hard drive (usually done via DeployStudio or Target Disk Mode.)
Intel, PowerPC G5, or PowerPC G4 (867MHz or faster) processor
512 MB of RAM
9GB Hard Drive space
There is a Universal 10.5 image for use on gala.cs for older macs.
Notes:
This is the last Mac operating system that supported PowerPC based Macs.
The processor speed requirement can be bypassed (if the machine at least has a G4 processor) by directly imaging the Mac's hard drive (usually done via DeployStudio or Target Disk Mode) though it is not recommended due to the lack of proper graphics support on older machines and speed issues.
Mac OS 10.6 "Snow Leopard"
Dropped all PowerPC support, all Mac OS versions after this are Intel only
Information in this area is meant for use by CSCF staff and is not official documentation, but anybody who is interested is welcome to use it if they find it useful.