I just found out about an augmented reality easter egg hidden in the Yelp.com iPhone application. This is great news for All-You-Can-Jet pass holders looking for bites on the road in cities they probably won't have enough time to research before the journey sets off in less than two weeks.

Mashable reported the new feature in the Yelp app called "Monacle" earlier today, which has been hidden to bypass any detection by Apple's reviewers, since Apple was waiting for the iPhone OS 3.1 release to let developers use it. Nice job Yelp! Basically, the "Monacle" feature allows you to hold up your phone while using the Yelp iPhone application, and (using the internal compass), will visually show you the name and rating of a restaurant you are viewing through the iPhone camera. It only works on the iPhone 3GS; sorry slackers.

How it works:

• Download the updated version of the Yelp iPhone app, which came out yesterday. (You iPhone might trick you into thinking you have the most updated version. If that's the case, just search the app store and re-download it.)
• Open the Yelp app and shake it three times. A window will pop up saying the feature has been activated.
• You will now have a "Monacle" button in the top right corner of the Yelp app. Click it and go!

I tested it out, and although it seems to think I have a deli in my house, I'm sure it's a few tweaks away from being close to reality. I can see this feature falling into the hands of advertising, showing you pop-up specials and promotions while viewing the world through the eyes of your iPhone. Would that be such a bad thing?