Locking up your iPhone with a passcode prevents mischievous friends from looking at your pics and emails, and makes it harder for thieves to access your data before you get around to wiping it. For even more security, there's the password option, which gives you more than just 4 lonely digits.
As great as passcodes and passwords can be, they're fairly annoying when you just want to make a phone call. To place a call, you have to slide to unlock, enter your code, open the dialer, and select or dial your contact. This process can be sped up by asking Siri to place calls for you from the lock... more