GroundBound
Most of the IFR books are adequate as far as I am aware (certainly the Tom / Pratt books seems to cover the IMC rating syllabus fairly well). The Confuser, a few years back was a bit of a let down (had quite a few errors) but I heard it is now okay.
IO540 makes a sound point. Your best ground training would be to read through the textbook, get yourself some "plates" (airport Instruments procedures) study them and then fly it on the sim. Then study in detail the log and see how you did. You'll find its not easy.
I get a lot out of mine (OnTop) - I often practice an ILS with wind, turbulance and windshear set. A few sessions on it certainly make the impending IFR flight much easier.