Harry Himself A Horcrux? Or Is That Hokum?

What clues has J.K. Rowling herself dropped? Snape: Villain, hero or something else?
Who dies in Book 7? Ralph Fiennes -- born to play Lupin, not Voldemort? If you're interested in those topics see previous posts, below.

Other than the discussion about whether Harry will have to die in order to kill Voldemort [(n)either can live while the other survives: Trelawney's prophecy recounted in Book 5 (OotP)], the next most common line of speculation seems to be whether Harry himself is a Horcrux.

Note to slacker fans: You have to read Book 6 (HBP) to learn about Horcruxes. In brief, a Horcrux is an item that holds a piece of a wizard's soul, making said wizard sort of immortal. To make one the wizard has to A) Be to magic as Wayne Gretzky is to hockey and B) Kill someone. Voldemort has made six Horcruxes, Dumbledore speculates. Some are accounted for, some aren't.

A very astute Potter reader with whom I'm close is exasperated at all the people who believe Harry is the last, missing Horcrux and that's why Voldemort couldn't/didn't kill him as a baby and why Harry and Voldemort seem to share some mental connection.

I'll see if I can extract a paragraph or two from the "Harry's No Horcrux" side and post it, but it won't be until later today.

If Harry IS a Horcrux, that might mean he has to die for Voldy to die. Because otherwise Lord V wouldn't really be dead as long as Harry is alive.

After all, Voldemort could have used Lily's death to make Harry into a Horcrux. The question is, why would he do that if he wants the baby Potter out of the way? UNLESS someone else was there, perhaps hiding under an invisibility cloak that belonged to James Potter, and did something to make Voldemort's spell go weird. Dumbledore? Snape? Could Voldemort have been using James' death to try to turn Lily into a Horcrux? Does anyone know whether the Horcrux death has to happen before the Horcrux spell, or after?

Could Harry use the Prior Incantato spell (used by Amos Diggorgy in Goblet) on Snape's wand to get Dumbledore's ghost back? And if he does it, wouldn't that be too cheesily close to the Obi-Wan and Yoda ghosts who show up for Luke in "Star Wars"?

Is/was Dumbledore the Heir of Gryffindor? What does that mean for Aberforth, and his goats?