Oh gawd, I don't envy you at all! We flew to Perth (so only 3 hours time difference) a couple of weeks ago with our 2.5 month old and it was the worst thing I've done since he was born. It stuffed everything up (feeding, sleeping etc) and he is still having troubles 2 weeks later. I wish we didn't go (it was for my sisters wedding though) and wouldn't recommend it to anyone but sometimes you have to do what you have to do.
Riley slept well on the plane (but we couldn't because he was on our laps) but the time difference has just caused so many problems.
Good luck! I hope it isn't too hard on you all...