These are instructions on how to get Siri to recognize the names of your contacts. This is especially useful for names that are difficult to pronounce or are said different from how they're spelled.
Step One Launch Contacts from your Springboard or from the MobilePhone app.
Step Two Select a contact from your address book.
Step Three Press the Edit button at the top right of your screen.
Step Four Scroll down and select Add Field from the list of buttons.
Step Five Choose Phonetic First Name or Phonetic Last Name from the list of possible fields.
Step Six Enter the phonetic pronunciation of the name that Siri isn't recognizing then press the Done button at the top right of your screen.
NICKNAME You can also get Siri to recognize and refer to a contact or yourself using an entirely different name by adding a Nickname field to the contact entry.
I see the same option on my iPhone 4 when I follow the same steps. Is this really a 4S future? I'm thinking not- it probably dates back to the original voice control on the iPhone 4 (and probably older but I've never had older).
I would test it now but I'm at work...
Conversly you can just tell Siri to call you by your nickname and it'll automatically be added. You can also say things like Kyle is my brother and Siri will add it for you and recognize that Kyle is your brother from then on.