Amplitude Modulation (AM) Operation
This page talks about the Amplitude Modulation (AM) mode of operation.
The AM Wiki page is a good place to start for information about this mode of operation.
The American Radio Relay League (ARRL) has a great page that has links to a lot of good AM information, and some links to their articles on their AM Phone Operating and Activities Page.
The American Radio Relay League (ARRL) set up an AM station on June 18th, 2004, and W2DTC was there to get a few photos as this station came to life. He's got them posted on his AM at ARRL Page.