To be honest, I only remember it in vague details. If I must, I will make the trek all the way back to my high school library to search for this manga. Here are some details that may or may not help:
>The main character was a girl that was pretty good at singing
>She was singing at some sort of school festival and a news crew came to the school
>They would usually hang out on the school rooftop together
>One of the main love interest guys was a slacker that would basically never come to school