io9 has an article about how organisms are programmed to age and die as an evolutionary adaptation.
One of the researchers, Bar-Yam, believes that this aging process may be reversed. From what I've read, however, this is highly unlikely ('all the low hanging fruit have been picked'), but it's certainly an interesting idea.
Life extension always reminds me of Isaac Asimov, who described a struggle between long lived, risk adverse Spacers and their more numerous, shorter lived, breeder adversaries, known as the Settlers, in his Robot novels. The robots, naturally, were produced by the aloof, elitist Spacers, who needed manpower. Rather than opening up their perfectly ordered new worlds to immigration and letting in the teeming masses from the overcrowded, dying earth, they made synthetic laborers.
It's a fascinating series, and later in life he connected it to Foundation.
As we see demographic transition accelerate and life extension technology becomes a reality, will the world split into fecund, short lived societies and long lived, sterile immortal ones? Or will it be class based? Isn't that the dream of every despot? To rule for all eternity, forever on top, with disposable masses crushed beneath. Which just reminds me of Stargate.
One thing Asimov showed quite well is how changes in one area (say, life span) will affect many others. He was a writer who explored consequences.