14 DAY TRIAL // The first beta build for Windows Vista Service Pack 1 will be made available for download in September via TechNet. As of yet, Microsoft has failed to reveal the actual release date of the beta build for the service pack of Windows Vista. However, the Redmond company did point to a Vista SP1 beta launch prior to November 2007. Microsoft only committed to delivering the public version of Vista SP1 Beta by the end of 2007. One aspect that cannot be denied is the fact that Vista SP1 is continually evolving and, in this context, drawing near to the availability date.
Currently, Microsoft is dogfooding pre-beta releases of the Vista service pack, and has even released a couple of builds to a selected pool of testers. With all Vista SP1 info muted by Sinofsky's Windows Omerta, codename Translucency, details related to the builds already under testing are scarce, and just leaks and crumbs from the Microsoft service pack feast. But, apparently, Microsoft is closing in on taking Vista SP1 out of pre-beta stage and into actual beta phase. This could happen as early as next month, although the date was not officially confirmed by Microsoft as of yet, and has to be taken with a grain of salt.
Still, according to a discussion with an operator of the MSDN Concierge chat, courtesy of Sebastian Foss (thanks segobi) TechNet subscribers will be able to access download of Windows Vista SP1 Beta as early as September. This news comes on the heels of Microsoft delivering a new pre-beta build of Vista SP1 to testers. Build 6.0.6001.16633 (longhorn.070803-1655) of Vista SP1 is a standalone .EXE installer much in the same manner as the pre-beta download of Windows XP SP3, and not the 3+GB ISO image offered in mid July.
As of yet, Vista SP1 6001.16549.070628-1825 dropped in July is the only pre-beta build leaked to peer-to-peer file sharing networks. It appears that with build 6.0.6001.16633, Sinofsky has improved his selection of "selected" testers, and as of now, not a single screenshot of the second pre-beta version was leaked. I am going to try and confirm the September launch of Vista SP1 Beta from my sources and I will keep you up to date.