The best science I know about this is Morris and Thorne's traversable wormholes. Kip Thorne has a popular science book "Einstein's Outrageous Legacy" which very entertaining and also very scientific (ie. careful to distinguish what it speculation from fact).
For an excellent, non-technical reference, have a look at the second edition of Time Machines: Time Travel in Physics, Metaphysics, and Science Fiction by Paul Nahin. This is a wonderful book that is written for the educated layperson.
Physicist (and relativist) Kip Thorne wrote a foreword for the second edition of this book, and here's a quote from this foreword: "It now is not only the most complete documentation of time travel in science fiction; it is also the most thorough review of serious scientific literature on the subject - a review that, remarkably, is scientifically accurate and at the same time largely accessible to a broad audience of nonspecialists."
As atyy said, wormholes can be used to generate closed timelike curves, but wormholes require exotic material. I wrote about Morris-Thorne wormholes and closed timelike curves here (requires knowledge of special relativity):