Clients to find Personal Trainers

?I'm looking to develop an app for iphone and android where Clients can find Personal Trainers via geographical location, program type and price. Trainers website or page can be viewed in the app also. App could post to facebook, twitter on client behalf or trainer behalf. Trainers can advertise specials, programs and training locations (various if they train clients at various locations) and availabilities where clients may cancel at last minute. Clients could bid on trainers available spare time-slots - trainers can set minimum or reserve pricing. This pricing could be dynamic and increase in value automatically until auction end (set by the Personal Trainer). Clients could send trainers messages via SMS or eMail through the app. Trainers could sync their availability calendar such as google calendar, apple ical or MS Outlook calendar. (for instance I use Google Calendar) Payment for training could be through trainers preffered payment method - Maybe a later update or inclusion if there is demand.