At the moment I've been rocking the latest cut of mango, for the first time i had the phone bluetooth paired with my car whilst receiving a text, since the new update (this wasn't in the first few cuts of mango).
It immediately told me who I'd received it from, offered to read it to me, I said yes.
It did a cracking job of text to speech, then offered to let me call back the contact, dictate a reply or do nothing!
I really hope it makes it, its one of the better features, because I'll be honest, I've read SMS's before whilst driving on my own or flying solo....