I haven't got to the stage of approaching taxi companies yet- right now the app is really just a developed concept that I've entered into an app-making contest (http://2011.nycbigapps.com/submissions/5832-taxonomy) . It has VC investor judges, cash prizes, etc.- basically, I'm waiting to see what happens. If it gets a fantastic reception then yes, that's time to start approaching cab companies about direct booking etc.