Update 4/22/12: Michelle Michell posted in my FB page:
The Pledge of Allegiance and the National Anthem
In 2007, the U.S. Congress addressed etiquette for the pledge of allegiance and the national anthem in 36 USC 301. When saying the pledge of allegiance, citizens of all ages should stand at attention, face the flag, and salute by placing the right hand over the heart. Men should remove their hats, and women any sports caps.
Here is another link: