They trade jokes, chuckle and talk shop about a hacker plot called "Project Mayhem." But at the heart of the conference call between the FBI and Scotland Yard was a strategy aimed at bringing down the hacking collective known as Anonymous, which has launched a series of embarrassing attacks across the Internet. Unfortunately for the cyber sleuths, the hackers were listening, too — and now so is the rest of the world. Anonymous published the roughly 15-minute-long recording of the call to the Internet early Wednesday, gloating in a Twitter message that "the FBI might be curious how we're able to continuously read…