Not legally, no.
I am on 3.0....I have MMS working, should I start looking for the police to knock down my door? I think the word you were looking for was officially, it's not illegal to activate mms through at&t nor to alter the carrier file to get the options available in 3.0.
How do you get an "altered carrier file"?
I cannot get MMS to stay working... I get it to work for a short time, but whenever the ATT site changes my phone back to iPhone, i loose the MMS... What are you doing to keep it working???