CONCORD, N.H. - Democratic Sen. Barack Obama, who is mulling a presidential bid, will make his first visit to New Hampshire next month. The Illinois senator will join the state's Democrats on Dec. 10 for a belated celebration of their big win in the midterm election. Obama has traveled to Iowa, site of the leadoff presidential caucuses, but New Hampshire hasn't been on his itinerary. Obama has gotten encouragement to seek the presidency in 2008 from fellow Illinois Sen. Dick Durbin, who sent a letter to political supporters this week encouraging them to sign a "Run, Barack, Run" petition. "Barack...