Grown from embryonic stem cells, the technique will eventually allow drug testing to be carried out on cultured organs and even better, will eventually lead to entire organ replacement.
Now I'm wondering if this only works with embryonic stem cells, since the obvious advantage would be if you could grow organs from adult stem cells, because then you'd have no problems with rejection following a transplant. Perhaps it would be possible to replace the nucleus of an embryonic stem cell with one from your own cells? I'm sure I read a story about someone doing this recently, but I'm buggered if I can find it.