Today the Senate Committee on Commerce, Science, & Transportation held a hearing on Spam (Unsolicited Commercial E-Mail). "Description: Members will hear testimony relating to potential legislative, technical, and other approaches to curtailing unwanted spam. Senator McCain will preside." The committee provides the full-text of available testimony via this main link.
See also, Microsoft Proposes Law on Junk E-Mail, Spammer Urges Congress to Pass Anti-Spam Law, and Gates Sends Letter on Spam to Congress.