I also have been using this - initial idea was put out by Jon B. a few years ago with the idea of the pt. paying some nominal fee for the service. It is a great idea.
I have been slowly getting my patients introduced to the idea with electronic media in the office and just this week the company put out a letter to all my active patients and linked a microsite on the net with the same video and ability to sign up online.
The company is much like Amazing Charts in that you can talk with the CEO and discuss options and they are responsive and trying to make the service better.