As posted on the Windows Vista blog at 10 AM today... The public can sign up (in case you missed your opportunity to check out Beta 2) to get the bits for 32 and 64 bit versions.
As I have previously posted here and here - if you already have a Beta 2 CPP key, you have probably already been informed of the download locations and the fact that you DO NOT NEED TO RE-REGISTER to participate. All you need is the ISO image and you are good to go.
If you forgot your key - you should have received an email earlier in the week with a notice and a republishing of your key (mine came in on Monday night at 8:33 PM).
While you are at it - get the bits for Office 2007 B2 Technical Refresh. They are live as well.