Bootable dmg from xp help?????????????

ok i have a mac powerbook g4 and i got it with no OS of any kind on it i was able to get it up and running using ubuntu linux so now i really want a mac OS on it i have downloaded what says it is mac OSX10.4 and it is in dmg i need to burn this so i can boot it in the mac so i can set up a mac OS i have also downloaded whats say to be OS9 to i have tryed a few ways and every burn i do has been a waste of my time only thing i can get to boot in it has been the ubuntu linux so please any help would be great and renaming the dmg to iso still dose not boot for me burns but no boot also some of my downloads i can't even find a way to rename the file thanks for any ones help oyea i know it's breaking the law to download software so please no one waste my time telling me that ok