Inorder to use Mobile Hotspot on your iPhone, you got to have either one of these plans $19.99 Sprint Mobile Hotspot - 2GB or $49.99 Sprint Mobile Hotspot - 6GB.
Use the following steps to set up Personal Hotspot:
1.Tap Settings > General > Network
2.Tap Personal Hotspot and turn it on:
3.Choose whether to enable Bluetooth or Wi-Fi and USB (Wi-Fi requires iPhone 4 or later, or iPad (3rd generation) Wi-Fi + Cellular).
4.After configuring Personal Hotspot, you can directly access the settings from Settings > Personal Hotspot.
Hope this helps
i just got my new iphone and i am trying to figure out how you set up the hot spot on it..