It's been interesting to see payphones disappear - up here in Northern California, at least - as more and more people get cell phones. Well, we thought the preponderance of cell phones was the reason for the pay phone's demise, but maybe the problem was that they just weren't as useful as they used to be. AT&T wants to put the phone booth back in play, with a few added high tech tricks. Today, the company unveiled public telephones that combine Internet connectivity and other online services, such as e-mail, with voice calling. The new AT&T Public Phone 2000i is being rolled out initially in major U.S. airports for use by travelers. The fee to use all of the capabilities is 25 cents per minute, with a four-minute minimum. The unit accepts credit cards or cash - $1, $5, $10 and $20 bills - for payment. Additional features include a 12", touch-sensitive screen and a touch pad integrated into the keyboard.