Generation Dead by Daniel Waters

What would you do if the dead don't stay dead? All over America, dead teenagers are coming back to life. Nobody knows why. They are trying to act like regular kids, they go to school and listen to music. But people are not prepared to accept the living impaired or differently biotic. Instead, they call them zombies, corpsicles or dead heads.

Phoebe isn't sure what to think of the differently biotic kids at her school. There's Collette, a former friend of hers whom she hasn't talked to since she died. And then there's Tommy. For some reason, Phoebe can't explain it, she's interested in Tommy Williams. Tommy isn't your regular differently biotic kid. He can talk and move faster and he's trying out for the football team, which goes over real well at prejudiced Oakvale High.

As Phoebe and Tommy become friends, she unknowingly draws her other friends into the tensions surrounding the differently biotic and traditional kids. As the violence against the dead kids grows, Phoebe, Tommy, and their friends try to promote peace and tolerance.

But there are some who believe the dead should stay dead, and they're out to permanently kill all of the Generation Dead.