That's a little tricky - the earth being round and all. You can't put a satelite in orbit around New York (in spite of it being the center of the universe - orbital mechanics doesn't work like that)

Your only real option is how close to the equator you orbit them - you can get away with about 3 sats if you only want to cover the region very near the equator, unfortunately only poor people live there. As you improve coverage further north you have to add more satelites in higher inclination orbits. Iridium already limits this - the coverage in the far north is very poor, which is ironic since it's one of the few places where you really need sat phones!