Hey kersny,
Thanks for the link, I read about their filter, very interesting. I have been testing my own digital high pass filter to get rid of some of the drift. The problem is for pure panning motion, there is no accelerometer information available to correct the gyro, so their code will not work. I think it may be possible to correct drift when your head is not perfectly straight up though, but I have yet to get my head around it (so to speak :D).
-Z-