People who receive potential scam emails can report them to the FBI, the Federal Trade Commission or the Financial Fraud Enforcement Task Force. Many companies also provide an email address for customers to forward scam emails sent under the guise of being a representative of the company.
The FBI has a website, the Internet Crime Complaint Center, where people can file complaints about scam emails. The Federal Trade Commission lists an email address to forward phishing emails to on its website and also has a complaint website for victims of scams or phishing emails on which to report incidents. The Financial Fraud Enforcement Task Force maintains a website for people to report many different types of fraud, including computer-based fraud and identity theft.