Perhaps you've seen the the jailbreak hack that allows you to use Siri hands-free but haven't wanted to jailbreak your device. Lucky for you, there's a built-in feature that'll let you use Siri without the need to press and hold the home button. To set it up, just follow these steps:
- Open the Settings app on your iPhone.
- Tap the General tab.
- Tap the Siri tab.
- Toggle the "Raise to Speak" option to the "ON" position.
Now anytime you raise your phone to your face to talk (and aren't in the middle of a phone call), Siri will activate and await your command. This is, of course, only useful if you're not using a headset.