The Blue Board

I took it awhile ago. The GMAT has a strange way of grading. Basically, they will start you off with a middle of the road question. If you get it right, you will get a harder question. If you get it wrong, they give you an easier question. The score is then based on the level of question that the test has zeroed you in on. It is VERY important to get your first several questions correctly. Take extra time on them if needed.

As for what to study, just get a GMAT prep book and you will be fine. Make sure you brush up on your geometry and trig. Also, if you haven't written any short answers recently, you might want to do some practice on that as a chunk of the score is based on the written portion of the test.

MBA.com is a good starting point. Written portion did not matter on the old exam, although they just changed it, so there may be some weight added there.

Math is going to be the toughest to rise in, the raw score vs percentile ranking in Math is much higher than Verbal.

These are a couple of helpful websites...

http://gmatclub.com/

http://www.beatthegmat.com/