The latest issue of magazine Doctor Who Adventures (No. 255) has some new information on Aliens Vs Wizards with a quote from Russell T Davies:
Aliens Vs Wizards is the story of a family of Wizards who face big trouble when some nasty aliens arrive, hungry for magic. Russell says:
"Wizards have never met aliens before, and when they do, the result is spectacular! The Nekross know exactly what to do with magicians. Eat them! Let battle be joined!"
Check out who's involved in the series and read more details about AvW here.