Thankfully, I have deboarded this boat. I was a religion/philosophy/greek major - no time at all for sciences as an undergrad. Now I'm getting a master's in Molecular Cell Science. I took the MCAT last spring and ended up with a 10VR, 12PS, 10BS - having just finished organic chem. and genetics. I had not had most of the physics, and it had been some time since I had taken general chemistry. I studied by butt off in those subjects, however, and ended up doing better in phys. sciences than in Biol. sciences, subjects in which I had had more formal education.
I didn't take any review classes; I bought the Kaplan textbook and memorized every subject that they said appears on the Physical science section...all the formulas in the MCAT book. I cut-up index cards into 1/4 sections (1.5x2.5 inches) and wrote all the formulas and constants on them, punched a hole in the top left corner of each card, and put the cards on rings arranged by subject area. I carried one of these around with me everyday and would go over the material whenever I had to wait in line, sit in an elevator, etc.
If there were any subject area for which I felt I didn't understand the concepts I would pull out my textbooks (Cutnell and Johnson Physics - might as well be "for idiots"; and General Chemistry by Hill and Petrucci). I'd review the chapters and make sure I could work a few of the problems given. If you devote a few hours, you can easily knock a chapter off in a night (given a few hours) - that's a whole subject...if you make the little cards you can keep reviewing.
For me, the practice tests were more important for getting me used to the MCAT format and timing, etc.