EFF and other fine groups announce DETEKT, a spyware detection tool. It’s a joint project with Amnesty International, Digitale Gesellschaft, and Privacy International. Read the disclaimers and instructions carefully.
Note also that they seem to be on a very short release cycle: I downloaded version 1.1 at work yesterday (nothing detected), and just downloaded version 1.3 at home today.
Disclosure: I’m a proud member of the Electronic Frontier Foundation Advisory Board.