The devs have said all along that we'll be getting patch 3.0.3 before Wrath of the Lich King launches, and it's pretty obvious that we will. It's a pretty important patch overall. The game is playable without it, but there is a lot of balance fixes in the patch that is crucial to the launch of a whole load of new content. I don't doubt we'll get it before we hit Northrend. The question is... when?
Will we get it tomorrow? It's a possibility, but from the sounds of things it's kind of unlikely. I don't think we've ever had a patch didn't happen on a Tuesday (though I may be mistaken), so if it's not tomorrow that only leaves November 11th for a patch prior to launch. Alternatively, maybe they'll roll it out the night of Wrath's launch, so when you pop in those install discs you get to patch, too. Considering midnight launches though, it would be really unusual if they rolled out the patch the evening of November 12th. Personally, my money is on patch 3.0.3 being pushed live on November 11th, and if the devs announced patch maintenance for tomorrow while I write this I am going to eat my hat.