Door-to-door shared-ride van services are available at all terminals at Chicago O'Hare. They depart from the Arrivals level of the terminals.
Shared vans cost from $25-$40 per person depending on drop off/pick up location. Companies that provide this service include:
Go Airport Express - 888 284-3826
Omega Airport Shuttle - (773) 734-6688
Coach USA Wisconsin - 877 324-7767