blotunga: Almost none. Maybe a bit from the first book. Anyway the only annoying thing about a Song of Ice and Fire is that G.R.R. Martin hasn't finished them yet. I just hope it won't happen as with Dune :/. That's why I refuse to buy/read them for now :)
GRRM has actually fielded that question on his "Not a Blog" from his website. He said the question was rather rudely posed to him, noting he was fat, old, and probably wouldn't finish the series before he died.
His response, was that even though he is fat and old, he has left a lot of great notes on how he wants the Series to conclude. He has even fleshed out a lot of the series in his notes. So, he said if the unfortunate should happen to him, someone could take his notes and finish the story the way GRRM envisions it.