Any Metallica fan with an iPhone or iTouch should drop whatever they're doing -- work, family, friends, whatever -- and prepare to spend the rest of the day browsing through the band's excellent, newly updated  'Live Metallica' app.

Quite simply, it's a well-organized, easy-to-use application that allows you to listen to a great deal of live music from Metallica's career for free, and gives you the chance to purchase just about, as the sales pitch says, "every live note Metallica has played since 2004" in MP3 format.

The band's most recent concert (at the time of this writing, their April 2011 appearance at the 'Big 4' festival), is always available for streaming, along with a rotating selection of shows from across their career. From the looks of it, today you can listen to something from every one of the band's tours, all the way back to their 1982 club days.

Exclusive photos and comprehensive notes from the show, detailing when they last visited the city and venue, as well as what songs made rare appearances in the setlist that night, are also easy to enjoy.

And how's this for organization? Seven years ago, I bought a concert download from the band's website, and as soon as I logged on to the Live Metallica app this morning, it was waiting for me in my downloads folder. That's treating your fans right!

So, if you're a Metallica fan, by all means, you should pony up the ninety-nine cents and buy this app. That way you'll have music for your big road trip to Yankee Stadium this Sept.14, when Metallica and their 'Big 4' buddies hopefully put a big metal hex on the team that Major League Baseball players say features the three most overrated players in baseball.

(Editor's note: The author of this article is a diehard Red Sox fan who has recurring nightmares about Bucky "F---ing" Dent and Aaron "F---ing" Boone. This sort of stuff is therapeutic for him.)

Watch Metallica's 'Big 4' Yankee Stadium Teaser Clip