If you downloader for the new patch is slow (mine is, at least) or not working at all, then check out the posts of Sero96 and LippoW in the Curse forums. They have found additional ways of getting the patch.
Read in the downloader FAQ, that it's supposed to be slow, as to not cause lag ingame. That's also why it started downloading a month in advance.
Fair point. However, the wow downloader uses a torrent, which you can actually extract and use in a torrent program of your own choice. This is a much preferable solution for people with problems downloading as the wow downloader itself has no configeration options for people behind firewalls and routers they have no control over (on campus or at work, for example)
The various download sites (fileplanet, fileshack, filefront) usually have it soon after it is released. Fileplanet lets you sign up early to receive priority downloading.