For me it is Cambridge preparation for TOEFL Test. Make sure to have the right edition - I guess it was the forth (for the IBT).
I would recommend you to take Kaplan Toefl Practice tests.....it's good and very helpful. There are websites that have study material, practice tests, prep course, online live classes on TOEFL. Online Live classes are worth taking as they are provide classes online and you can clear your queries then and there.
