"I'm very pleased to announce that Microsoft has acquired Winternals Software and Sysinternals. Bryce Cogswell and I founded both Winternals and Sysinternals (originally NTInternals) back in 1996 with the goal of developing advanced technologies for Windows. We've had an incredible amount of fun over the last ten years working on a wide range of diverse products such as Winternals Administrator's Pak, Protection Manager, Defrag Manager, and Recovery Manager, and the dozens of Sysinternals tools, including Filemon, Regmon and Process Explorer, that millions of people use every day for systems troubleshooting and management," writes Mark Russinovich, who is now best known for exposing Sony's rootkit-style CD protection.
There's also a Microsoft press release which says: "Russinovich will join the Microsoft Platforms & Services Division as a technical fellow, working with numerous technology teams across Microsoft, and Cogswell will join the Windows Component Platform Team in the role of software architect."