It will open a new window with the full message including complete headers. With the Messenger component of Netscape Communicator 4.0, pull down the View menu, choose Headers, and choose All. An alternative is to pull down the View menu and choose Page Source. It will open a new window with the full message, including complete headers. In the Pine mail reader, you can hit H while viewing a message to see the full headers, if that option is enabled.
Spammers sometimes put fake headers at the end of a message to cause confusion.
However, AOL is virtually the only environment where headers are supposed to show up at the end of a message, and even there you should be able to find the real headers after the fake ones. You can use these fields to decide where to report the spam. Opinions differ about the best strategy, and this explanation will be kept simple at the risk of offending those who hold different opinions. This machine shares some of the blame, since it should have detected that the message was spam, for example because its return address could not be translated to a legitimate IP address, and refused it. This is where it helps to have technical tools for reconstructing the truth behind potentially forged e-mail headers.