GREdic word list - An extensive GRE word list with detailed definitions.

Graduate Record Examinations - The official site by Educational Testing Services (ETS). Test registration, information for policymakers and teachers, and sample questions.

GRE Vocabulary Sound Files - Offers a large vocabulary list in a sound file in mp3 format.

GRE Quizzes - Contains nine multiple-choice quizzes, with score tracking.

Vyom Educational Resources - Large and small vocabulary lists for the GREs and TOEFL as well as over 1000 practice antonym questions.

GRE Vocabulary Quiz - Online quiz, consisting in matching words with definitions, in multiple choice format.

GRE Vocabulary Builder - Offers for download a freeware program with a customizable wordlist.

Guru's Home - Offers a freeware program for vocabulary review including a customizable and sortable wordlist. Also sells a CD of the program to students in India.