location aware article via NYTimes:
...personal location devices are beginning to catch on, largely because cellular phones are increasingly coming with a built-in tether. A federal mandate that wireless carriers be able to locate callers who dial 911 automatically by late 2005 means that millions of phones already keep track of their owners' whereabouts. Analysts predict that as many as 42 million Americans will be using some form of "location-aware" technology in 2005...
...(Graham Clarke, president of National Scientific, which makes several G.P.S. tracking devices) recently installed a tracking device called Followit in the Jeep Wrangler of his 17-year-old son, Gordon. It alerts him if Gordon has exceeded 60 m.p.h. or traveled beyond preset boundaries...
...And for Donna Phillips, 66, whose husband, Hubie, has Alzheimer's disease, the ability to lock a G.P.S.-enabled bracelet from Wherify Wireless around Mr. Phillips's fanny pack when he goes out has meant an end to panicked searches when he fails to come home. Now her granddaughter can help her find her husband on the Wherify Wireless Web site, which displays the location information transmitted from the bracelet when an authorized user logs on...