When Sen. Hillary Clinton runs for reelection in 2006, her opponent might just be another high-profile attorney from Westchester. Westchester County District Attorney Jeanine Pirro is considering challenging the former First Lady, according to political insiders. The GOP crimefighter, who is running for reelection this year, is not publicly discussing plans for higher office. But Pirro has a dizzying fund-raising schedule and the enthusiastic backing of Gov. Pataki. "We love Jeanine," said a source in Pataki's camp. Sources say it is becoming less likely by the day that former Mayor Rudy Giuliani, who may be eying the White House, will...