What started out as a moderately useful gimmick to view the entire width of a Web page or a photo in its proper landscape ratio has turned into one of the iPhone’s greatest assets. With the overwhelming success of the App Store, iPhone’s accelerometer suddenly has a million and one uses, turning the handset into everything from a fishing pole to a plumb bob--even a tectonic plate.

Here’re 12 of our favs:

iBeer/iMilk/iSoda

A simple sight gag, sure, but we can’t salute the accelerometer without paying a little homage to one of the original novelty acts. While not the cheapest of thrills at $2.99, these three apps are the best possible advertisement for the brilliance of iPhone and the technologies therein. Tilt the phone to “drink” the beverage; shake it to create more suds--or heavy cream, in the case of iMilk. Turn on “dirty mode,” and your beverage will even leave behind residue as you pour it. How cool is that?

Instapaper

Even if we overlook how our new favorite app has made our iPhone that much more indispensable, we have to take a moment to praise one of the most ingenious implementations of the accelerometer we've ever seen: tilt scrolling. After collecting a handful of Mac|Life articles you couldn't get to during the day, Instapaper presents each one in a neat, easy-to view format that can be read from beginning to end without ever touching the screen; turn on tilt scrolling, and you can pan through the story simply by tipping your iPhone ever so slightly--or farther back for you fast readers. It's so brilliant, you'll fret ever having to turn a page again.

Snail Mail

Winner of IGN’s Best Use of Accelerometer award last year, Snail Mail is the quintessential iPhone game, leveraging iPhone’s tilt controls to put you right in the center of all the slithering action. Like Need for Speed, your snail mailman is controlled directly by accelerometer movements, but there’s more to this game than simply staying on the track--any number of obstacles, enemies, weapon rings and power-ups await you around each twist and turn, and the game’s precision tilt controls make it a gooey guilty pleasure.

Labyrinth

Like a classic that never goes out of style, the ol’ guide-the-ball-to-the-hole-at-the-end-of-the-maze puzzle game never gets tired. It was fun when it was carved out of a wooden box, and it’s nearly perfect as an iPhone app. With precision accelerometer controls and realistic gameplay, you just might forget there isn’t actually a tiny silver ball clinking around inside your iPhone.

iFishing

While most captains are lured to Flick for their off-the-water flounder fix, it doesn’t win our award for Best Use of iPhone as a Fishing Pole. That distinction goes to iFishing, which recreates the experience with a bit more realism, casting your line based on the actual direction of your flick, rather than assuming a straight toss. And once your hook is in the water, iFishing handles the natural movement of the rod better, too, mimicking the subtle jerks and tugs of the open water, while also responding to the fisher’s own movements. Just like a fishing boat, without the nausea.

ShakeItPhoto

Digital photos may be superior to film in most every technical way, but there’s a certain nostalgia that today’s cameras can’t recreate. But thanks to iPhone’s accelerometer and a little out-of-the-box thinking from Nicholas Campbell, the tedious, yet-oh-so-satisfying completion of a cropped, dated Polaroid snapshot can now be enjoyed without carrying around a clunky instamatic camera. And you can even listen to “Hey Ya” while you shake it... shake it... shake it like... well, you get the picture.