There is already a thread on this film, I'll find the link to it in a moment.
Anyways, just incase people have'nt read the other thread yet or seen the film (I haven't yet) then here is the answer in spoiler.
Appartently, Fast & Furious is set in-between the 2nd and 3rd film, therefore Han is still alive and within the 4th film he mentions about going to Tokyo or something.