When describing a black hole evaporation in the hawking black body radiation it is usually said that is due to a virtual photon pair, is it this what happens? And what is virtual photon pair, does the photon has anti particle or it is its own ? I am not looking for a deep theory, just the general picture.
As Anna says, while it's commonly stated that Hawking radiation is due to one member of a particle anti-particle pair falling through the event horizon, this is nothing more than a metaphor and it's not actually what happens.
I actually answered this question is some detail in Black holes and positive/negative-energy particles, but I suspect this answer may be overly complex. The phenomenon is related to the curvature of spacetime. Have a look at my answer and if you want to explore any of the points I discuss post another question and I'll help if I can.