No offense intended, Saxman, but I think you’re a little off point. The OP was whether Islam enjoins the killing of nonbelievers, not how it says to treat noncombatants. To me, at least, those are different issues.
I found an article titled “The Religious and Moral Doctrine On Jihad” at http://www.islaam.com/ilm/ibnta.htm. Of course, one website doesn’t represent all of Islam, but the site as a whole doesn’t seem to me to be exceptionally fundamentalist or radical. Someone more familiar with Islam than I am would be in a better position to evaluate that. Anyway, you can read the article for yourself, but here are some quotes – fair use, I hope, and not too far out of context. All the parenthical notes, except the one noted, are in the original.
“That then is the jihad against the unbelievers (kuffaar), the enemies of God and His Messenger. For whoever has heard the summons of the Messenger of God, Peace be upon him, and has not responded to it, must be fought, “until there is no persecution and the religion is God’s entirely.” [K., 2:193, 8:39].”
“As for the People of the Book <Christians and Jews – note by Whiffet> and the Zoroastrians (Majoos), they are to be fought until they become Muslims or pay the tribute (jizya) out of hand and have been humbled.”
“Since lawful warfare is essentially jihad and since its aim is that the religion is God’s entirely [2:189, 8:39] and God’s word is uppermost [9:40], therefore, according to all Muslims, those who stand in the way of this aim must be fought. As for those who cannot offer resistance or cannot fight, such as women, children, monks, old people, the blind, handicapped and their likes, they shall not be killed, unless they actually fight with words [e.g. by propaganda] and acts [e.g. by spying or otherwise assisting in the warfare].”
“The most serious type of obligatory jihad is the one against the unbelievers and against those who refuse to abide by certain prescription of the Sharee`ah, like those who refuse to pay zakaat, the Kharijites and the like. This jihad is obligatory if it is carried out on our initiative and also if it is waged as defence.”
“So the latter [form of jihad] consists in defense of the religion, of things that are inviolable, and of lives. Therefore it is fighting out of necessity. The former [type of jihad], however, is voluntary fighting in order to propagate the religion, to make it triumph and to intimidate the enemy, such as was the case with the expedition to Tabook and the like.”
The article does say that captured persons should not be harmed, but this protection apparently doesn’t extend to male combatants who are captured:
“The Sharee`a enjoins fighting the unbelievers, but not the killing of those who have been captured. If a male unbeliever is taken captive during warfare or otherwise, e.g. as a result of a shipwreck, or because he lost his way, or as a result of a ruse, then the head of state (imaam) may do whatever he deems appropriate: killing him, enslaving him, releasing him or setting him free for a ransom consisting in either property or people. This is the view of most jurists and it is supported by the Koran and the Sunna.”