The first two minutes of the Doctor Who 2008 Christmas Special just aired as part of the BBC'S Children In Need charity night, and you can also watch it online here. Looks like David Tennant has finally found someone who enjoys saying "Allons-y" with as much gusto as he does. To donate to the Children In Need appeal, click here.
I'm pretty sure the Doctor wasn't quite so keen to advertise the fact he was a Timelord within two seconds of meeting a stranger, nor that he felt the overwhelming urge to dandy himself up in period costume - I'm thinking a smart-arse impersonator. And good call on the "sonic" screwdriver in the trailer.