You can use Voice Control (iPhone 3GS only) to call someone in your contacts or dial a specific number.
NOTE: Voice Control isn’t available in all languages.
Press and hold the Home button until the Voice Control screen appears and you hear a beep. Then use the commands described below to make calls.
You can also press and hold the center button on the iPhone headset (or the equivalent button on your Bluetooth headset) to use Voice Control.
Say “call” or “dial” then say the name of the person. If the person has more than one number, specify which one you want to call.
Examples:
Call John Appleseed
Call John Appleseed at home
Call John Appleseed, mobile
Say “call” or “dial,” then say the number.
For best results, speak the full name of the person you’re calling. If you give only the first name, and you have more than one contact with that same name, iPhone asks which of those contacts you want to call. If there’s more than one number for the person you’re calling, specify which number to use. If you don’t specify which number, iPhone asks you which one to use.
When voice dialing a number, speak each digit separately—for example, say “four one five, five five five, one two one two.”
NOTE: For the “800” area code in the U.S., you can say “eight hundred.”
In Settings, choose General > Passcode Lock and turn Voice Dial off. Unlock iPhone to use voice dialing.