The Three Souls of Harry James Potter (Abandoned, Archived)

When James and Lily learn about the Prophecy and that their son is Voldemort's target, the couple decide to look at old rituals in the hope of finding a way of protecting Harry. James and Lily do find a ritual but it has the strange result of bonding James and Lily's souls to Harry's, forcing them to stay alive through their son. It does allow them to talk to Harry, thankfully.