Startup idea: web2.0 rendez-vous organizer

I've seen a startup here in France offering a web service allowing customer to pick themselves the appointment date. They login and the free slot agenda is presented to them. They can then reserve the time slot they want or change it later. This avoids blind and long discussion through phone with the secretary. Of course the client is given a password controlled access so that he is identified. This service was sold but was far too expensive. A freemium business model should be offered instead. Another very useful service is the one provided for free (with ads) by www.doodle.ch allowing for a group of people to converge (by vote) on a meeting date. It is nice to have it free, but in a company we would prefer one without ads and hosted internally for confidentiality. A company would certainly be ready to pay for such an application. Beside I'm quite sure a more user friendly and ergonomic interface could be invented.