I thought WidowPC's dead pixel fixer looked interesting. It's a epilepsy-inducing movie you are supposed to run on loop behind a dead pixel overnight, and it might be able to un-stick it. I have no idea whether or not this actually works, as I've had the incredible good fortune of never owning an LCD with any dead pixels (over an old Dell laptop, a PowerBook, a 19" display, a PDA, an iPod nano, and a cell phone!) but I can't think of how it would hurt to try if you suffer from this all-too-common problem.
This thread on Applegeeks has a couple testimonials that the thing does sometimes work.