Today, Diana makes her long awaited appearance in Smallville Season 11 #16 by Bryan Q. Miller and Jorge Jimenez. This arc will encompass four print issues. You can also expect an eventual appearance from Felix Faust.
If you're someone like me who hasn't been entirely happy with Superman in the New 52, I highly recommend you check out the Smallville Season 11 comics. They're canonical with the TV show and the first two arcs- Guardian and Detective- are now available in trade paperback.