I generally root for the little guy in antitrust complaints (assuming their claims are valid of course), but I also enjoy watching two massive monopolies or near-monopolies duke it out over antitrust issues.
Google is now complaining because Microsoft is bundling Windows Search with their Windows product. Of course, Google fails to mention that Microsoft has been shipping a poorer, but still present version of Windows Search for years.
Antitrust law is intended to protect competition, not individual competitors! Microsoft is not bundling disparate products together here like they did with Internet Explorer and Windows in the late 90's. Windows has always had desktop search, they've merely improved it. Unlike web browsers, searching for files has always been an integral function of a desktop operating system and placing false limitations on the improvement of that function merely because Google decided to enter a market based almost entirely on the weakness of a core Windows function is absurd. This is about as stupid as Anti-virus vendors getting mad because Microsoft is adding anti-virus functionality to Windows (something that is definitely much needed, not anti-competitive). Apple's Mac OS X has for over 2 years now included similar search functionality. And last but not least, Microsoft announced that search would be part of Vista before Google ever announced or released Google Desktop.
I run a Mac primarily, so this complaint seems exceptionally odd considering that the Mac version of Google Desktop not only runs side-by-side with Apple's Spotlight desktop search technology, but also utilizes it and adds value to it. Why can the Windows version of Google Desktop not do the same? Many people would still find value in the product if it added Gmail and Google Docs support over normal searching for instance, which is what it does on the Mac.
While I often root for the victims of monopoly abuse, I don't think this is the case here. It looks to me more like sour grapes and a diversion over the much more serious antitrust concern over Google's purchase of Doubleclick.
While that complaint is also being pursued by 2 massive corporations, both of which have colorful antitrust histories, the complaint seems much more valid to me than Google's concerns with Windows Desktop Search.
Unlike Desktop Search, ad networks are products that are paid for and serve a purpose. Google Desktop Search was merely produced to exploit a weakness in Windows XP, one that was fixed (not added) in Windows Vista. Google also has a massive footprint in the online advertising market, one that it expanded greatly when it acquired Doubleclick.
Personally, I think the government should continue keeping a close eye on Microsoft and begin to do so on Google. Both companies are big enough and powerful enough that they both warrant antitrust monitoring. Google trying to paint Microsoft with an antitrust brush, and vice versa, is laughable at best.