UPDATE 8/16: The roster update has been released for the 360/PS3. Look for all the details including the document laying out every change made to be up soon.
I have confirmed that a roster update for Madden 08 will be coming in the very near future. It will likely find its way out before the week is up and may even be as early as this evening. However given the nature of these things EA can't narrow it down to a specific time.
Please be aware that when the roster update is pushed it may disconnect those who are playing online games at the time.
While this update will be for the Xbox 360 and PS3 versions, an update is also planned for the other systems. No time frame has been given on when those can expect to receive it.
I was not able to confirm yet whether Michael Vick will be removed from the game in this update. Given the current circumstances surrounding his case, there is a chance he'll be completely removed, or he may just be dropped to the bottom of the depth chart.
Check back tomorrow as I am expecting to have a document detailing every change that was made within the roster update.