All of the guys in the know say that Korea is the track that sees the greatest improvement in lap times over the course of a weekend. The reason being that the track is totally green on the Friday and gradually rubbers in to the point where lap times can improve by up to 5 seconds.
The fastest time in FP2 was that of Sebastian Vettel at 1m 38.832sec: the pole time in 2011 was set by Lewis Hamilton at 1m 35.820sec, and by Vettel in 2010 at 1m 35.535sec in 2010. That's a difference of over 3 seconds, and last year, even though quali was dry, the weekend overall saw a lot of rain falling on the track.
I'll be interested to hear what time Gary Anderson predicts for Pole Position, given that we haven't had a dry GP in Korea over the last two years.
Ultimately the Free Practice times are meaningless in predicting the grid, but having said that, at the back of the grid FP can indicate who's moving forward and can give a third driver the chance to impress, which none of the managed to do this morning; van der Garde was seven tenths behind Kovalainen while Bottas, and Clos were over a second behind their established team-mates in FP1.