SpyBot S&D (for “Search & Destroy”) is a great little utility that will help you find adware, tracking cookies, and other little nasties. I had been using an earlier version for a while (more to keep an eye on what cookies are being used for than anything else), and now v1.3 is out. SpyBot S&D is free, and is well worth the download (Windows only). The SpyBot homepage is at http://www.safer-networking.org/.
…that site always is yelling about CGI limits or some jazz. Got a direct link?
URL seems fine for me, download link is http://www.safer-networking.org/index.php?page=download.
You can download it from http://www.download.com. Search for spybot.
I have been using it for 6+ months (and occasionally Adaware). I’m quite happy with it.