Microsoft bought out Mark Russinovitch and his companies SysInternals and WinInternals last year. The Sysinternals tools remain freely available as before, while the Wininternals tools are generally targeted for the Desktop Optimization Pack. I'm sure that everyone that reads this site has used the tools Regmon, Filemon, and the Process Explorer from the SysInternals side.
The ProcessExplorer was updated a short while back and, of course, is more powerful than ever. I heard about this new tool last week from some Microsoft folks, and now here it is released. ProcessMonitor is the replacement for FileMon and RegMon, as an all in one tool. No more launching one and then the other and trying to cross reference timestamps! It also updates those tools for the new operating systems, adds in new filtering options, and adds in a boot-time logging option. While it does not include the ProcessExplorer, you can click on a captured line and get some process/stack information about the process that caused the event (if it is still running).
The is an excellent replacement for Filemon/Regmon for the toolset. Microsoft did change the license slightly, but basically they are just trying to prevent folks from distributing the bits from anywhere other than the Microsoft site. You can read more about the ProcessMonitor, and download the bits from http://www.microsoft.com/technet/sysinternals/utilities/processmonitor.mspx