Wired News article on the FBI sting on a Russian hacker - the so-called 'Invita' case. A US federal judge gave the FBI the authority to hack the Russian's computers on Russian soil.

Presidential Decision Directive 63 describes the need for critical infrastructure protection from attacks of may types (including cyber)

HSPD-7 is a document which categorizes the threats to critical infrastructure (see PPD 63), and assigns the responsibilities of protecting those infrastructures to various federal agencies

A good guide to the many U.S. supreme court resources on the web