For those interested in taking the GRE General CBT (computer-based test), the closest CBT center is Oklahoma City. You can call 1-800-GRE-CAll or the OKC center directly, (405) 947-6248, to schedule a test. You will need to go to www.gre.org for registration, test dates, and information.
For those interested in taking the GRE Subject test they are administered at Cameron University once a year. You will need to go to http://www.gre.org for exact test dates, registration, study material and information.