An American consumer is suing Apple and iPhone operator AT&T for the failure as yet to deliver the promised MMS messaging on the iPhone 3GS.

Deborah Carr has filed a lawsuit in Ohio that charges Apple and AT&T for "violating laws against deceptive trade practices and with breach of contract" for stating that the iPhone 3GS offers such a service.

Announced at the device's launch in June, US users of the iPhone 3GS are still waiting for the multimedia messaging, a disappointment Carr's lawsuit prices at $5 million.

Officially, in small print, Apple said "MMS support from AT&T will be available in late summer". This apparently gives Apple and AT&T until 22 September at 5.18pm EDT, when "fall" officially begins, to introduce the service.

"Millions of customers, as a result of the false and deceptive representations and concealments of Apple and AT&T purchased the 3G and 3GS, waiting for the wonderful day in June 2009 when the new application would be available which would allow MMS", Carr's filing reads.

"Unfortunately, after downloading the new 3.0 Software Update application, MMS still did not work on both the 3G and 3GS".

We will keep you posted with developments.