Formerly know as It and by the code name Ginger. The invention that claims it will "change the world" and be bigger than the Internet. Here's some excerpts of what the New York Times is saying:

"It is not a hovercraft, a helicopter backpack or a teleportation pod."

"The mystery transportation device being developed by the award winning inventor Dean Kamen - the subject of continuous speculation since provocative clues and predictions surfaced in media reports last January - is not hydrogen powered, a favored theory in Internet discussions. Nor does it run on a superefficient Stirling engine- yet."

"Mr. Kamen plans to demonstrate today a two-wheeled battery powered device designed for a single standing rider. Its chief novelty lies in the uncanny effect, produced by a finely tuned gyroscope balancing system, of intuiting where its rider wants to go -and going there."

"The device, the Segway Human Transporter, better known by its former code name - Ginger, can go up to 12 miles an hour and has no brakes. Its speed and direction are controlled solely by the rider's shifting weight and a manual turning mechanism on one of the handlebars."

"Tilt sensors monitor the rider's center of gravity more than 100 times a second, signaling to the electric motor and wheels which way to turn and how fast."

"The United States Postal Service, the National Park Service, and the city of Atlanta plan to begin limited tests of the devices early next year. Amazon.com and several companies that make parts for the Segway, including GE Plastics and Michelin North America, plan to use the devices to try and save money by reducing the time it takes employees to move around corporate campuses and large warehouses."

"At an average speed of 8 miles an hour, or three time walking pace, Mr. Kamen says the Segway can go 15 miles on a six hour charge, for less than a dimes worth of electricity from a standard wall socket."

The Times further states...

"The Segway is meant to be ridden on sidewalks, and many municipalities ban motorized devices on sidewalks. The machines weigh 65 pounds, and although they may be able to zip in and out of elevators and offices, going up and down stairs is a different matter. The device can be put in "follow mode", which helps propel it up and down, but there is still lifting to be done. Each one comes with a computer encoded on-off key protected by 64-bit software encryption to deter thieves or joyriders. But locking the machine to a parking meter or lamppost is far more awkward than doing the same thing with a bicycle."

Update:

It should be noted that as of April 2013 the Segway never really caught on and from the looks of it, it never will. In a bit of gallows humor, Jimi Heselden, the multi-millionaire owner of the Segway company, died when one of them he was riding plunged off an 80 foot cliff.

That's not what I would call a huge selling point.