On Monday, Microsoft released a new version of its Windows AntiSpyware tool (reportedly soon to be renamed Windows Defender.)
If you're not currently using an active-defense anti-spyware tool on your Windows PC or if you're using an older version of the Microsoft AntiSpyware tool, you'll want to get this:
Windows AntiSpyware Beta Updated (Nov 21, 2005)
Main improvements: The expiration date for this version is July 31, 2006... and it finds and removes the Sony DRM rootkit.
For the record, I actually prefer and recommend CounterSpy, which costs $20 and is well worth it, as the standard anti-spyware tool of choice for Windows machines. It's built on the same codebase, from Giant Software, as the Microsoft tool, but has more stringent and aggressive rules for spyware identification and removal. And Counterspy's publisher sells a second copy half-price for two-computer households; you can protect your desktop and your laptop for $30.