Read the complaint. The plaintiff is alleging that AT&T did claim it was a feature of the iPhone, before their network supported it.
I didn't read all the details, but it appears to be a complaint about false and/or misleading advertising.
I DID read the complaint and "the details." The plaintiff is claiming that MMS is STILL not available...
"31. Thus, it became clear that AT&T’s network does not support MMS.Totally false... as are the claims that AT&T advertised MMS availability on the iPhone before it was available unless there were ads in New York that were different than the ones I saw in California or on the Internet.32. When calling Apple Customer Support, it was revealed that AT&T has never upgraded its network so as to support the functionality necessary for MMS.
33. Accordingly, the iPhone cannot offer MMS as claimed and represented by the defendants.
. . .
36. Upon information and belief, to date, AT&T has failed to upgrade its network to support MMS.
37. When and if AT&T upgrades its network, the millions of iPhone purchasers will get what they bargained for in terms of MMS. In the meantime, all the millions of purchasers of the 3G and 3G-S iPhone have been deceived and cheated out of what they thought they were purchasing - a cell phone with MMS functionality. 38. Apple and AT&T representatives continue to misrepresent and/or conceal, suppress, or omit material facts to customers in their stores about the MMS functionality of the 3G and 3G-S iPhones."
—Complaint filed November 16, 2009
There are other errors of fact presented in the complaint, as well.
Apple's world wide advertising for the iPhone DID truthfully claim MMS capability, but always asterisked it with the statement that in the United States AT&T did not yet support MMS.