This is a polling trick. If "approve" and "disapprove" switched places, the results would be the opposite. The subconscious mind remembers the last option the most. It is the last word it heard, and the respondent unconsciously responds to it.
Now reread the question again....
1. Do you disapprove/approve of the way George W. Bush is handling his job as president? Do you disapprove/approve strongly or somewhat?
"Feel" the difference? It's slight, but the first question was negative in nature. The second was positive in nature.