Microsoft this week delivered different Release Candidate 1 (RC1) versions of Windows XP Service Pack 3 (SP3), Vista Service Pack 1 (SP1), and Windows Server 2008, setting the stage for the final rollouts of each OS update in early 2008. None of the releases include any notable functional updates over previous beta versions, but each has now progressed to a point of maturity that Microsoft describes as near-final. Best of all for those interested in these releases, each will be made available to the public in various ways.

For Windows Vista SP1, the RC1 release brings no major changes, but does include a number of feedback-related enhancements. For example, SP1 RC1 requires far less free disk space during installation, and provides more guidance about the update earlier in the installation process. Microsoft is shipping SP1 RC1 to testers today, and to MSDN and TechNet subscribers on Thursday. Next week, the company will make the release available to the public via a Web download or, optionally, Windows Update.

Meanwhile, the RC1 version of Windows 2008 will be made available to the public by end of day today, Microsoft tells me. This release doesn't include any functional changes over the previous pre-release build, RC0, but it does feature better fit and finish and performance, and bug fixes.

XP SP3 RC1 was the first of the three releases made available, with Microsoft shipping the update to MSDN and TechNet subscribers on Tuesday. XP SP3 doesn't include any major functional changes, but it does collect the several hundred hot-fixes that have shipped since 2001 along with a few minor updates. It's unclear if XP SP3 will be made available to the broader public, but I've got more information about this release on the SuperSite for Windows if you're curious.

I will also be discussing Vista SP1 RC1 and Windows 2008 RC1 later this week on the SuperSite, along with information on obtaining the Vista SP1 RC1 release.

In related news, Microsoft will ship the first service pack for Office 2007, SP1, next week. Office 2007 SP1 isn't expected to include any major new features, but will instead collect various hot-fixes that have shipped since the product was finalized in late 2006. The Office 2007 SP1 beta has been a secretive affair, for some reason, and little is known about the contents of this update.