If you're DEDICATED, just buy the EK complete study package, EK Audio Osmosis, EK Verbal 101, EK Bio 1001, and all the AAMC exams. Maybe the big Kaplan book as a backup.
Even if you haven't traditionally been super motivated/organized in your undergrad classes, if you're motivated enough here, you should be able to create/stick to a solid schedule. Find the EK 10 week study program and go from there. You can tailor it slightly to fit your own schedule, but it's a great setup. I've always received good grades in school but have always had issues with self motivation and organization; however, for the MCAT, I knew my life practically depended on my score (not really, but it feels like it....) so I made the sacrifices and put my plan into action. For several months I lived, breathed, and slept MCAT (on top of other undergrad courses).
I ended up with a very satisfying score, and several points higher than I would've expected 6 months before I took the real thing.
If you've got the time/money, it couldn't hurt to do the class. But if you're not made of money, the above materials may be all you need.
By the way, EK Audio Osmosis is great not only for drilling concepts into your brain for the MCAT, but also very helpful for your undergrad pre-req's. I first got them right when I was beginning to take Physics I, and listening to them on the way to and from classes and such helped me get a better understanding of the fundamental (and some more obscure) ideas of the course, which I certainly think helped me ace the class. My professor was, on several occasions, impressed with my ability to think critically about certain topics and answer some "difficult" questions of his in lecture. The only reason I could even begin to do this was from hearing about the stuff on EK AO. But, I digress.