A federal judge denied bail yesterday for an American student charged in an alleged conspiracy to kill President Bush after an FBI agent testified that the man had admitted plotting with al Qaeda to conduct a Sept. 11-style terror attack in the United States. Ahmed Omar Abu Ali, 23, of Falls Church, told FBI agents that he and other members of an al Qaeda cell in Saudi Arabia planned to hijack airplanes overseas and crash them into targets on the East Coast, according to testimony. They also discussed plans to kill members of Congress, blow up ships in U.S. ports...