Tethering in Iphone 4 - Movistar Argentina

• General → Network → Cellular Data Network
• Under "Internet Tethering" we write:
  APN:internet.gprs.unifon.com.ar
  Username: internet
  Password: internet
  
• Turn on and off
• General → Network → Personal Hotspot and swipe to on
• Select a password and you're done!