No specific date has been set.
We'll find out if we get greenlit on November 30th. We should be greenlit then as we're in the #2 spot and they'll be greenlighting at least 10 games.
After that, it should hopefully be not more than a few days to sort out the legal paperwork, then maybe a week or two for Steam API integration and packaging for Steam distribution.
If there aren't too many delays or unexpected technical glitches then we should be on Steam before Christmas - just in time for the holiday sales