(This sounds as if it it will be delivered with Windows Vista.....)
..........Windows Defender is about what Windows will do for customers, defending them from spyware and other unwanted software. Our solution has really been about more than just the standard definition of "spyware". We’ve always said we will provide visibility and control, as well as protection, detection and removal from other potentially unwanted software, including rootkits, keystroke loggers and more.
Making the engineering change from "Windows AntiSpyware" to "Windows Defender" took a lot of careful coordination across our team to ensure that the strings in the UI got changed, the help files all got updated, registry keys, file names and properties, as well as a couple of images all got changed. All this work was completed and tested last Thursday, and is currently making its way through our build systems in Windows to make it into the main build environment, where official builds come from.
....the sleek new UI and other improvements we've been making in it to help make Windows Vista the best operating system around! But Windows Defender is about a lot more than just a name change. The engine is now moved to a system service, and signatures are delivered over Windows Update. The detection mechanisms have also been radically improved by applying to spyware threats all the great detection technology we use in our antivirus engine.
Read full article: MS AntiMalware Engineering Team Blog»