Leave your iPhone at our friends house and you're afraid he's going to find those text messages you sent to his mom? Now you can remotely lock your iPhone with MobileMe with iPhone OS 3.1.
This is a great way to keep people out of your iPhone if you happen to leave it somewhere but don't need it remotely wiped.
Log into to your MobileMe account.
Click on the Account Settings icon.
You'll be prompted to re-enter your password.
Click on Find My iPhone on the left hand side of the page. Under Find My iPhone you'll see the new Remote Passcode Lock feature.
Click on it and you'll be asked to enter a new passcode twice before it's sent to your iPhone.
Once the new passcode is set, it will erase your former passcode if you had one. Also, the iPhone will be set to use a passcode in order to unlock it.
To turn this off navigate on your iPhone to settings > General > Passcode Lock. You'll be prompted to enter your passcode. You can turn passcode off or change it from there.
