I just moved a few days ago and I would love an easier way of finding where to play basketball than calling every gym in town and asking tons of people for tips, which is what I started doing earlier today. I've also seen how the friction in this process makes lots of people simply stop playing basketball after they move away from their home town or lose easy access to a college gym, so the problem you're trying to solve is both real and important (and extremely difficult, of course).

But... I don't have an iPhone. Does it make sense to leave most people out, even for an initial launch? Especially since your biggest challenge will be getting critical mass in different locations.