...is a question I keep getting asked*. Now that we've announced that it's finished, people understandably want to get their hands on it. And rest assured, the product team is keen for you to get it too so it all bodes well.
This is being driven by people other than me, so bear that in mind and forgive me if this isn't as precise as it could be however the general approach is likely to be that MSDN subscribers will get it first, we'll email all preview program participants (ie people who got beta 2) and provide them with details, and are likely to then open up the program to everyone after that.
We will of course be giving away copies to people who attend our events, at least in the UK anyway. This should be the case for events happening from Oct 1 onwards. Keep an eye on our upcoming events site for event details.
If you have any questions feel free to ask, I'll do what I can to clarify them.
Oh, and register at http://www.microsoft.com/betaexperience/engb/ to keep up to date, and keep checking that site and/or http://www.microsoft.com/windowsvista/getready/preview.mspx
If I hear more I'll blog it as soon as possible of course :-)
* For the record, "RC1" is "Release Candidate 1" which, as the name suggests, is a version of the product that is being considered for release. It is much more stable and performant than the beta 2 version. There may be further RCs before the RTM "Release to Manufacturing" version which will form the shipping product.