Via Flicks and the City (which is a great source for interviews of film and television actors, particularly those based in the UK), there’s an excellent interview with Julian Glover, who plays Grand Maester Pycelle. He discusses details of the third season (including giving a taste of a scene he shares with Charles Dance), and also the way that his character was somewhat adjusted from what’s in the novels. Initially, the writers wanted Pycelle to simply be a dottering old man, but Glover indicates he grew tired of this and asked for more to do… and so they came up with the notion that his aged demeanor is a put on, a way to disarm suspicion and attention from himself. Of course, in the novels, Pycelle is rather less decrepit until events in A Clash of Kings than he has been played in the show.
You can see the interview below (and beware, there are spoilers for future season!):