I just took my ASTB a few days ago for the Marine Corps. I managed to pull out a 9 AQR, 9 PFAR. The info on this site for the aviation and nautical info test is a great place to start. Anyone who is taking this test should keep in mind that the ANT and SAT (spatial apperception) are weighted heavily for pilots. Unfortunately, there is no study material for the ANT (aside from practice problems), and the SAT examples in the ARCO guide are not very good. The real test will show the plane flying at various angles to the coast, not just parallel and perpendicular like the guide shows. I highly suggest to anyone who has the time read a few aviation and naval history books in addition to having a good grip on the physics of planes and boats, and the names for the different parts of planes and boats. You also need to know things like how an airport runway is laid out (lights, numbers, etc) and the US buoy system. Understanding the basics of navigation and meteorology is helpful too.
Here are some of the books and websites that I used (sorry, can't find them all). I think a few are listed in the material on this site, but I can't remember which ones. Anyway, I hope this is helpful for someone.
http://www.usafa.af.mil/dfp/cockpit-phys/cp_anch1.htm (this site is VERY basic)
http://142.26.194.131/aerodynamics1/ (more in-depth site, also some history)
http://www.boatsafe.com/nauticalknowhow/boating/6_3.htm (buoy and navaid stuff)
http://www.celestialnavigation.net/ (OK site, also has many links)
httP://www.airwarriors.com/ (of course!)
The Student Pilot's Flight Manual by William Kershner