Thanks DJ Prem for alerting us of this.
Microsoft has announced immediate availability of Microsoft® Windows Server SP1 and Windows XP x64 Edition Technical Beta, Release Candidate 2 build 1433. It is now available for download at https://windowsbeta.microsoft.com.
Note - This is the second major milestone and highest quality release to date for the beta. Microsoft asks that testers keep in mind that it is not final release quality and it should be limited to test machines
and thanks to CountryKING who also alerts us via BPN that Windows Update v6 Beta has started, currently anyone can access the site by agreeing to the terms "I have read the preceding information and confirm that I am currently a registered Microsoft Windows Update Beta user". Its unclear if this will remain so, as Microsoft were unavailable for comment at the time of posting.