I looked around in the 2/26 PC Magazine issue that contains the much-criticized Dvorak column on blogging. Dvorak's Inside Track column talks about keystroke loggers and spyware. He plugged Ad-aware, an antispyware scanner, noting that it found 26 systems hidden on his PC. See www.lavasoftusa.com to download it, if you can get through.
Then he mentioned SpyCop, which you can get from www.spycop.com or through Anonymizer. It looks for secret keystroke-logging software and retails for about $50. I think there's a free version, and you can get it bundled with other products.
I found a number of spyware programs on my system. They're gone now. I understand that there are some caveats - some software might be disabled, especially if it is popup-ad supported like Blogger.