So someone graffitis "BAD WOLF" on the side of the TARDIS, and the Doctor is seen chasing a little pig. Clearly that means that the wolf that keeps being referred to is the Doctor.
Also, I think by the end of the series there will be two types of Doctor Who fans:
1. The type who will be unable to stop saying "Fantastic!" all the time, and
2. The type who will be so sick of hearing the word "Fantastic" they'll start thumping people.
At the moment I'm leaning towards being type 1.