JERUSALEM (Reuters) - Secretary of State Colin Powell discussed the idea of a Middle East conference with Israeli Prime Minister Ariel Sharon on Sunday, but no venue, participants or timing have been set, a senior State Department official said. "The secretary talked to Sharon about the idea of a peace conference, noted that Sharon had proposed the idea and they talked about how it might be done as part of a way to move forward politically," the official added, speaking on condition of anonymity. "But there's still more discussion necessary on both sides to see how we would do it,...