Heard from Qing's blog, (I happened to miss that part too!!) that there is another scene in the movie Constantine after the credits. It showed that Constantine went to visit Chaz (the cabby driver) at his grave, put a lighter there & walked away. Then Chaz came alive and appeared to be half angel, half demon and flew away....

CONSTANTINE part 2.. rise of the half-breeds <--- pretty catchy title yah??