I hope it's okay to post an external link here. I've been writing blog entries about the GMAT, discussing how business schools use the AWA portion of the test, some GMAT strategy, and a few other topics. A lot of the content is based on official GMAC research reports, which provide a lot of interesting information about the test. Anyway, it's free to read, and if anyone's interested, you can follow the blog link from here:www.gmatix.com
Nov 2011: After years of development, I am now making my advanced Quant books and high-level problem sets available for sale. Contact me at ianstewartgmat at gmail.com for details.
Private GMAT Tutor based in Toronto