Preparation is already underway. Before you question my sanity, take a look at the facts. Some of the smartest humans on the planet are involved in a project called Human+. They are a non-profit organization "dedicated to the ethical use of technology to extend human capabilities." Although their website looks amature-ish and the photos of the people on there don't look like the type that would be working on the most controversial and ambitious project in human history, don't be fooled. They are headed by 2 doctors, David Pearce and Nick Bostrom. Read a little about them before you go any further and you will realize this organization means serious business.
Basically the goal of the transhumanist movement is to ultimately merge humans with machines thus making them immortal. Now obviously this is a long process and will probably take a few hundred years, but not much more than that, IF that. But the wheels are in motion.
It is inevitable that the ultra rich and powerful will be the first to have access to this technology. The way it all unfolds is hard to predict, but here is what I think:

If you were a paranoid person, you might assume that the folks who actually run the world, that small percentage of people with all the money and power, that they will take advantage of this technology when it becomes available and are probably overseeing it right now and have been from the beginning. And at the same time, are in the process of attempting to reduce the human population drastically in order to prepare for the posthuman era.
If you were not a paranoid person and trusted the morals of humanity, with the information available to you on this subject, you should assume that humanity is inevitably going to merge with technology and become something that will surpass anything science fiction has proposed in recent history.