MMS has come to the iPhone 3G and the iPhone 3GS. You’ll need to update your carrier settings by plugging in your iPhone to allow iTunes to see it, then go to “Check for Update.” The install just takes a second and you then need to restart your iPhone. When you do, your Messages app will gain a small camera icon to the left of the input box. Tapping it will bring up a screen allowing you to take a picture or video or to use an existing one from your iPhoto library.
