A report on Kotaku
citing a source at US retail giant Walmart suggests that Microsoft's new console is currently aimed at launching on Friday, November 8 2013, notably a week ahead of Sony's confirmed November 15th date for the PlayStation 4 (Nov 29 in Australia). The info reportedly comes from an internal Walmart memo listing the retailers upcoming midnight openings. Officially, Microsoft has still only named the month of November as the console's release window.
As kotaku notes, this information (presuming it's authentic) is still tentative, but it would make sense for Microsoft:
Note however that, unlike every other date listed, the Xbox One's lacks a "confirmed" status, suggesting Microsoft is yet to lock the date down.
The fact it's not locked down of course means the day could change, but it also suggests it's a recent decision. Almost as though Microsoft were waiting for Sony to commit to a day before scheduling their own launch, in order to get the jump on the PS4...
Of course, even if November 8 is the bonafide North American launch date for the Xbox One, it's possible, and perhaps even likely that we'll be running a little later here in Australia (the PS4 has a two week gap between the regions). With only a couple of months to go, an official confirmations shouldn't be too far away anyway.