Computer security expert Frank Keeney took me for an eye-opening ride around Pasadena, California. Frank brought along a notebook computer, equipped with a wireless PC Card and an antenna mounted on the car’s roof. In a half hour of “war driving” (as he called it), we accessed over 40 wireless networks in homes, real estate agencies, businesses, schools–and even a bank. I could have browsed the Web on someone else’s account or created a Hotmail account and sent untraceable e-mail. If we were unscrupulous hackers, we could easily have broken in and examined–or deleted–files on any of those wireless-networked PCs.