I sent out the first ones in the first week of November to overseas destinations as we have no way of knowing how long they will take. All have now gone out with the exception of one less important one that goes out in early December. To show you how slow Overseas mail (to Australia) can be, I was sent some C.D.'s on the 4th of November (from England) and they only arrived to-day!
I usually wait till the first or second week of December.... and for my really close friends I wait even more :P Till as close to Christmas as posible :D
I haven't sent any Christmas cards lately but we use to send them in the middle of December.
I have received them in the mail from friends/family as early as the 1st week of December.
I got one like two days ago :)
First week of December