I take it you mean a bootable CD or DVD? You can't with 10.4. There is something called BootCD that works with 10.3.9 and earlier. You can make a bootable flash drive with 10.4 and up but it only works with Intel Macs, not your PowerPC.

http://newsgroups.derkeiler.com/Archive/Comp/comp.sys.mac.system/2008-04/msg00060.html