Instructions: tap and hold on the text message AT&T sends you when you get a picture message. Press "Copy" and then come here. Tap and hold on the text box above, then paste the message in the box. Click "Get my picture!" and you'll be sent to the right place.
Pro-tip: Click the '+' on the bottom bar of the iPhone web browser and click "Add to Home Screen". Now you've got even faster access to your picture messages!
Since AT&T won't give the original iPhone the capability to display picture messages, at least we don't have to memorize jibberish logins and passwords to see the pictures that our MMS-enabled brethren are sending our way.