Hm...
I think what tomuea would like (among other things) is basically some guidelines on how to explain objective morality & argue for its existence. solomon is giving some of that but I would say that there needs to be the understanding of what happens when materialist philosophy is taken to its logical conclusions. Or any philosophy, really.
What Dawkins does is remove morality, period. So, there's nothing wrong, nothing right, but only things that we prefer. In a sense [according to that worldview], we should be calling things orange, blue, and red, instead of -right- and -wrong-.
I know this is one messed up philosophy. But sadly people hold to it. I will try to identify a few points of tension--points where their philosophy and their lifestyle clash, and more often than not, their philosophy is set aside because it just doesn't work.
The first is that upon removing morality, anything becomes 'right'. This is determinist philosophy, which says that anything that is, is right. I don't think your friend can live with this himself. Two ideas come to mind--
1. The first is what his reaction would be if he was wronged in some way. Perhaps kicked between the legs (I'm being serious here) for no reason, or someone set his house on fire; stole his car; raped his girlfriend or mother. Horrid, indeed. Yet what right, if there are no wrong actions, does he have to even think about protesting? Just because something is 'unpleasant' to him, is that really grounds to protest? Well, that's the only ground (unpleasant), then it isn't. For instance, I've got to write up some 12 page script; it is unpleasant, but it must be done. I would assume he would agree that even some things you don't like doing must be done. How else do people get anywhere in life?
2. The second idea is that horrid things that happen to people (i.e. torturing innocents) are just alright; though they are unpleasant. Again, something merely being unpleasant is not a ground to protest anything. Interestingly enough, words like innocent, guilty, and justice have no meaning at all when morality is removed.
What you want to demonstrate is that, according to a worldview without objective morality, one is living in conflict with himself, and thus is living in contradiction. The saddest thing about doing this is that some people, after having it shown beautifully to them, shrug it off, though they do so with much pain. As always--pray constantly.
Note that in our age words like love, dignity, and honor have lost...well...meaning. Love means sex, and dignity and honor are whipping bags and mocked ideas. So you'll have to show your friend what the word love means coming from a Christian.
Just incase I've totally missed the target, there's just one more thing to follow.
Being somewhat familiar with determinist philosophy, and having had people argue that genetics, social influences, experiences, and whatnot dictate our beliefs & actions...a few comments follow:
1. Good data, bad story. Yes, the human psyche can be studied. Yes, experiences affect us because we grow from them. Yes, genetics play a part. So? I would contest that experiences make up our character.
2. Man as a machine. I don't think people can really live with this. Man loves, because he is made in the image of God. We may be able to define love and certainly muddle what it is, but man still loves [and hates]. A book comes to mind...it's "Intellectuals" by Paul Johnson. Check it out.