Depends where you live?
I'm in the UK, and I got my 6800 from Overclockers.co.uk. They're charging more than MSRP; I paid £600 for the 6800, which is the suggested price of the XT! I was within 3 minutes of getting the XT last Wednesday - people who ordered around 14:30 got them, my order at 14:33 did not. They had major technical problems that caused their site to go down repeatedly, and the cards not to even appear on the lists for many people (me included for a long time). It was so bad that they didn't actually receive any orders until 14:20, despite putting the cards live at 14:00. Then their system didn't automatically take the order button down, so they took something like 1000 orders when they only had 100-200 cards. I was one who managed to place an order and so thought I might get a card, only to get a refund some hours later.
But the upshot of all that chaos was that they ended up disabling ordering before they'd sold all the 6800s, so they put some back on sale the next day, Thursday, and only announced it in their forum, which is how I got one.
Apparently a lot of people have managed to get one direct from amd.com. You can check that site wherever you live in the world. It doesn't even list the 6800s whenever I go look, but apparently if they're available to buy, they will show up and you can order from them direct.
AIBs will go live at 14:00 local time on Wednesday 25th. So be ready for then, have a bunch of possible sites open, get an auto-refresh script running on each site, and hope to have a lot of luck
Oh, and pay by debit/credit card if you can, instead of Paypal. I learned that Paypal orders can take 10+ minutes to get confirmed as paid, and the site may use the 'paid' time as your place in the queue, not the time you actually completed checkout.
Note however that overclockers.co.uk said that although they'd go on sale on Wednesday 25th, they wouldn't actually have any stock until end Nov or early Dec. So even if you do get lucky, there will probably be a 1-3 week wait. I don't know if that applies to all retailers or just some.
Of course there's also the 6900XT on the 9th
But at $1000 MSRP, that's a bit too rich for me..