Here is another link to the Guru 3D page with the Detonator drivers, the newest ones are generally at the top.....:
http://www.guru3d.com/files/detonator/
Version 27.70 is already out too......BETA reference of course, but so far pretty stable on my machine. And generally you won't find pre-release/BETA drivers on the nvidia site, just because of the fact that they are not supported. I imagine nvidia doesn't want floods of emails of support requests, which is why they don't post them. Don't ask me why they "leak" BETA/pre-release drivers, probably a marketing ploy or sort of a VERY informal test.