COLORADO SPRINGS, Colo. - Democratic presidential candidate Barack Obama promised on Wednesday to create new opportunities for national service that would give Americans a chance to fight growing challenges on issues like poverty, climate change and education. On a trip to Colorado, which Obama hopes to turn into an election battleground in his November White House race with Republican John McCain, Obama said Americans were ready to answer a new call for national service. "I won't just ask for your vote as a candidate -- I will ask for your service and your active citizenship when I am president of...