Depending on whether you want it badly enough immediately, you CAN pay the required annual subscription fee (few hundred U.S. dollars) and download the final version (Build 7600) from Technet Plus right now. The next option is to wait until Oct 22 when it becomes generally available.
You can, however, borrow a RC copy (build 7100) from a friend and use the same activation key that they used and use that until Jun 2010. If you have a copy, you can install and activate it until Jan 2010, but it is already pulled from the Microsoft server and cannot be downloaded. This is a completely legitimate installation if you choose to do so. This only applies to the release candidate (Build 7100), not the final version (Build 7600).
Sorry, but Microsoft is no longer offering the RC as a download. You can still use the RC if you have a copy of it. If you have a friend who has an RC DVD, you can copy or borrow that for installation and your current activation key will work. (There is no prohibition on copying the RC version, because it was provided to the general public free of charge.) As I stated, you can install and activate the RC version until sometime in January and it will be valid until June 2010 regardless of when you installed it.