As posted above: Powerscore - you can find a bunch of old tests, the Games Bible, etc.
I also tried to find and read high-level articles...I chose to subscribe to "The Nation", but there are several of good mags, scientific journals, and newspapers out there. Find something that you will enjoy reading and that challenges you.
These give you an opportunity to critically read when you can't necessarily pull out the testing materials.
Honestly, I should have picked up some of those little game books that are similar to the logic games on the test. I think more practice on those would have helped me.