MALVERN, Penn.--I'm posting from the gymnasium of Great Valley High School in Malvern, Penn., where Barack Obama is set to speak any moment to a full house of students and local voters. There's the usual ruckus: chants of "Ba-RACK O-BAM-a" and "Yes, We Can" interrupted by half-hearted attempts at the wave and the occasional cry of "Woo!" from an impatient teenage girl. I'll be back with a report after the event, and then it's off to Levittown on the New Jersey border, where the Illinois senator is scheduled to address another high school later this afternoon. Stay tuned for more...