What did Michio Kaku say about it? Was it just a thought experiment based on time slowing down as you approach the speed of light (i.e. like the one about a twin who travels off somewhere at the speed of light, returns to find that his sibling and the world has aged 10 years, but he himself hasn't), or was he serious about it? I know Stephen Hawking mused about it in a documentary. Basically he said that it would be theoretically feasible to go forward in time (for you) if you had the technology to travel at the speed of light. You could not travel backward, however (maybe b/c of entropy/unidirectionality of time?).
Anyway, by reading the links given by others, you will probably find something more feasible that also interests you.
Good luck.