Spyware is Already Illegal, But Let's Pass A Law Banning It Anyway:
Are you annoyed by spyware? Would you like it to be illegal? Well I have good news for you: it already is.

  Most spyware violates 18 U.S.C. 1030(a)(2), part of the Computer Fraud and Abuse Act of 1986, which broadly prohibits unauthorized access to computers. Most spyware also violates equivalent state unauthorized access laws, too (for a review of these federal and state laws and what they do, see this article). Federal or state prosecutors could bring criminal cases against spyware companies for installing spyware at any time. Some spyware also appears to violate the Wiretap Act, 18 U.S.C. 2510-22, which prohibits intercepting your private Internet communications without your consent. The Wiretap Act authorizes both criminal and civil suits — and the civil suits provide attorney's fees, statutory damages, and even the possibility of punitive damages for victorious plaintiffs. And to the extent that spyware involves deceptive trade practices, spyware can also be regulated by the FTC. I'm not an expert in the jurisdiction of the FTC, but my understanding is that it is broad enough already to regulate spyware.

  Of course, you'd never know this if you followed recent goings on in Congress. Various bills have been proposed that would (gasp!) make spyware a crime, or else give jurisdiction over spyware to the FTC. I haven't looked closely at each of the proposed bills, but the ones I did look at seemed to mostly replicate existing law. Maybe the folks in Congress just don't understand current law; it's possible, given that the Justice Department has't pursued any spyware cases on the criminal front, the FTC apparently hasn't regulated spyware aggressively, and plaintiff's attorneys don't understand the Wiretap Act well enough to see the claim. Or maybe Congress just wants credit for solving a problem, and they won't let the fact that they already solved this problem a long time ago get in the way.