If Hermione has anything to do with it, I'm sure they can. ;-)
The locket might be at Hogwarts.
There's also the possibility that Mundungus Fletcher nicked it and either has sold it or will try to sell it. Remember, Harry's found out that he's stolen Black family property from 12 Grimmauld Place and is attempting to sell it and pocket the money himself.
Fletcher is currently residing in Azkaban. If he hadn't sold it already (assuming he took it), it's either stashed away somewhere, or the Ministry has it. In either case, I see Harry making a trip to Azkaban to interrogate Fletcher.