A nice find from the vaults at YouTube. I'm not sure where it comes from, one of the Ghibli DVDs, perhaps. It also appears to be an incomplete clip. But I think you'll enjoy the opportunity to hear two great artists share their thoughts for a few moments.
If I'm not mistaken, this would have been around a decade ago, judging from Miyazaki's facial hair and final touches of his original hair color. But don't quote me for any specifics.