I am skeptical about the 400,000 year age claim as well - I have yet to read what method was used to date the tooth. Certainly, C14 will not go that far back, if indeed it could be used on a tooth.
Didn't they say they just found it on Saturday or Sunday last week and are already claiming to know the age?
BTW, is that supposed to be an actual picture of the tooth in question? The guy is just holding it there in his bare hand?
Maybe it is just me, but I would have thought they would have tried to keep it out of possible contact with modern human DNA -