WSJ.com - Your Space Is Waiting: Reserving a Parking Spot

"MobileParking LLC has a service in which users call 800-PARK-123 to check parking availability and reserve spots at roughly 400 parking facilities in Baltimore, Chicago, New York and Philadelphia, among other cities. The Bowie, Md., company plans a nationwide launch of the service later this year when reservations will be possible at roughly 1,000 facilities around the country.
MY SPACE


See some of the services that allow you to reserve parking spaces online or over the phone.XM Satellite Radio Holdings Inc., which already provides real-time traffic information to navigation devices, demonstrated a potential service called 'Dynamic Parking Information' last November. The percentage of spaces available at certain parking facilities was represented on navigation-system maps using colored icons. The actual number of spaces available also was depicted.
The data came from sensors in garages in San Francisco, Los Angeles and Detroit. XM is in talks with major parking companies about putting sensors in their garages and providing availability data."