The Princeton Review: GMAT
- Provides classroom and online courses.
- http://www.princetonreview.com/mba/testprep/testprep.asp?TPRPAGE=3

Wikipedia: GMAT
- Article that gives an overview of the Graduate Management Admission Test.
- http://en.wikipedia.org/wiki/Graduate_Management_Admission_Test

BusinessWeek GMAT Prep
- Advice on taking the GMAT test and sample practice tests.
- http://www.businessweek.com/bschools/gmat/

Veritas
- Offers preparation and one-on-one tutoring centers.
- http://veritasprep.com

The Delta Course
- Online GMAT study course, test debriefings, and advice on stress. Practice test with immediate feedback. [Requires subscription]. Offers daily GMAT practice questions by e-mail.
- http://www.deltacourse.com/

Manhattan Review
- Preparation courses in Germany, and MBA admissions consulting.
- http://www.review.de/gmat-en.html

Graduate Management Admission Council
- An educational association provides information about MBA programs, financing, student preparation products and GMAT registration.
- http://www.gmac.com/