Can you rest the bar across your back? Upper is better (IMHO) but you can keep it a little lower around your rear delts as well. To emphasis what wukka said, if there is one exercise one could do for the rest of his life, it should be squats. And dont be one of those dbags that does like 500 lbs for a quarter squat.
I heartily accept the motto, "That government is best which governs least"; and I should like to see it acted up to more rapidly and systematically.