It's called ZocDoc.com. It is a secure website that lets you search doctors by their specialty.
You can also find out if they take your insurance, see when appointments are open, and book the appointment instantly.
It even works when the office is closed.
"Patients can use it at their convenience. I get a lot of emails that a ZocDoc appointment was booked when people get home and have time. They don't have to try to fit it in," said Dr. Monica Boyle of the Skin and Laser Surgery center of Pa.
Dr. Boyle also says ZocDoc frees up office staff to spend more time with patients and it helps keep her schedule full.
The site was created in New York by a frustrated patient.
It's now in 12 U.S. cities, including Philadelphia.