We knew it would happen eventually, but we figured it would take longer than a week.

Just days after American Airlines made the big-deal announcement that it had rolled out in-flight internet on certain routes, hackers have found a way to use the service for voice-over-internet protocol calls, despite promises from the airline that its air-to-ground system, developed by Aircell, would block voice calls.

A tip before we go any further: Voice calls on airplanes will result in chatty passengers who yap their way through an entire six-hour flight, which is likely to increase the chance of an air-rage incident. Fly at your own risk.

The workaround, called Phweet, allows users to call friends who are linked via Twitter. Andy Abramson from VoIP Watch says that he recently used Phweet to chat with a friend on an American Airlines flight, and that the conversation was so clear he could hear the flight attendant ordering people to get back to their seats in preparation for landing.

Phweet is a shortURL link to an external directory (for now, only

Twitter, though others will be added later), that enables calls between two or more profiles without sharing any additional information between the parties. Using the application to make calls at 27,000 feet is a painless three-step process:

Go to the Phweet homepage and log on with your Twitter name and password. Add the Twitter user name of person you want to connect with, along with a message telling them want to talk. A Twitter update and Phweet URL

is sent. When your friend clicks on the Phweet URL and accepts, your browser whistles and a Flash widget appears. Click on it to talk.

A spokesperson from Aircell told Wired.com that the company was aware of the Phweet workaround. "At American's request, we set up various mechanisms to block voice calls. Obviously someone found a way around them." She added that although it's up to American to enforce its no-call policy during flights, Aircell is doing everything it can to address the issue.

*Photo: TheHobbyGuy/Flickr *