After a long exhaustive wait, AT&T has finally enabled multimedia messaging service (MMS) for iPhones. In doing so, they have proven the worth of their word when they announced previously that they will be activating MMS “by the end of summer.”

Apparently, AT&T will be sending a text notification to their subscribers, informing them that the MMS function in their iPhones is already activated. But if you haven’t received the text message, here’s how to turn on MMS:

Connect your iPhone to your computer.

Select the iPhone in the left pane.

Click the “Check for Update” button.

A dialog should pop up, telling you that a new carrier file is available.

Download and install it, click OK when you’re done, then reboot your iPhone.

So for AT&T subscribers, I think that this is another indication you should leave your Blackberries in exchange of the Apple iPhone.