If you're an iPhone user on the AT&T network (I know that some of you are not ...) then by now you should have MMS (or Picture Messaging) capabilities enabled on your iPhone.
Wow, MMS capability I hear all you non iPhone users say. Hasn't that been around for years? Why, yes it has. Apple isn't adding anything new here, more just playing catch up, and if it were anyone else other than Apple adding MMS to a cellphone, we wouldn't be talking about it. That said, I like the fact that with the iPhone now you don't need to worry about choosing regular text message of MMS at the start. If your message contains only text, it's a text message, if you add a photo, it becomes an MMS message. Certainly simpler than my Nokia E71.
Note: Jailbroken iPhone have had MMS capability almost since the iPhone first came out.
Don't have it yet? You need to take your iPhone, hook it up to your computer, fire up iTunes and run the Check for Update feature to download the update. Once you've done that, make sure MMS has been enabled for you by going to Settings -> Messages. You should see an option to turn MMS on. Now, every time you compose a text message, you'll notice a new camera icon you can tap to select a photo to attach to the message.
If you're an iPhone user, have you started sending MMS messages yet? If so, what do you think?