The next big World of Warcraft patch has started pre-reloading as Blizzard attempt to try to stop the Internet from coming to a screaming halt. You can (I believe) use the normal Blizzard downloader to nab the pre-load files, but if you're really hardcore and want to nab them in advance and set them up manually, you can download the blobs
locally from AusGamers now. Note, this is
not the patch and it's only worth downloading if you're prepared to fiddle around a little bit - read the instructions on the download page for more information.
We'll update this file with the regular patch once it is formally released, so if you can't be bothered messing around with it then stay tuned.