Whew! This thread is all over the place, theologically. I'm afraid I just skimmed it, but I did note Curmudgeon's post. He's exactly right - the word "El" (one of the Hebrew words for God - it's what you see in the Hebrew Scriptures as "God," as opposed to "Lord) is the same root as the word "Allah." "Allah" simply means "God," so the Muslim Creed statement of faith should be read in English as "There is no God but God, and Mohamed is His prophet." Since Islam acknowledges both the Hebrew and Christian scriptures as sacred texts, I think there can't be much doubt that they're one and the same deity.
It's an interesting idea, though, that there would exist two different beings - God and Allah. Is that what your friend was arguing, Kendall? Does he believe both of these beings actually exist? If so, he might have something in common with the most ancient of Hebrews, who believed that there were other gods, but that theirs was supreme. As far as I know, however, that belief hasn't been current in Judaism or Christianity for many thousand years.