[eluser]Stefan Hueg[/eluser]
Such a booking system is one of my currently active projects.... and let me tell you: It's pretty complicated. It took me over 2 years to get it where it is, with nice features and such and you really have to have a good insight into the daily businesses of booking agencies in order to get a product into a usable state.
I just can't give you advice as my time is limited and if you don't plan to have any unique features, I'd say its a waste of time. The market is fed up with booking systems.