Until very recently, the word venue was only used as a legal term. Now it has taken on a meaning something like, a site where some sort of major event takes place.
Since the new meaning of the word hasn't yet become fixed in the language, the new usage isn't firmly defined yet either.
Judging by the way I've heard the word [mis]used, I'd say, "what is the venue..." is the more popular (but not necessarily more correct) choice.
- For Teachers