The popular iPhone app Urbanspoon is taking aim at its larger rival OpenTable.
The new system launched with just four restaurants in Seattle, but is expected to eventually expand into all of the 90 markets it serves.
Urbanspoon's iPhone app has been wildly popular. It averages more than one-million "shakes" a day, according to the company.
Both the iPhone app and the Web site started with limited features but it has developed more services, such as online menu previews, restaurant reviews and more.