Is a good place to start. But it is NOT a place to take online amateur radio tests. There is NO SUCH THING. All testing is done in person.
This is the website for the semi-official representative organization of amateur radio, the American Radio Relay League. Another organization involved in testing for licensing is W5YI (Google the website)
Amateur radio testing is done through an FCC approved "Volunteer Examiner" system (VE). I myself am an Extra Class VE and have tested all classes of license. Testing for licenses is NOT done over the internet.As I said before it is done in person at a testing session usually organized by local clubs or VE groups. The ARRL and W5YI both sponsor local groups who hold test sessions. Contact either of these organizations to find out about local test sessions.
You also might consider getting in touch with local amateurs in your area. Do a Googe search with your town's name and the keywords "amateur radio club". If you live in a small town use the name of the largest nearby city or town, especially if you live near a large city of 100, 000 or more people. A town that size is sure to have a ham radio club organized.
Once you find the club's website, send the president, secretary, or web administrator an e-mail to request info about joining the club and local VE test dates.
Now, aside from official testing, there are websites such as that offer practice tests. However, any ham radio mentor worth his salt will insist that you study textbooks such as ARRL's "Now You're Talking" to get your license. Online practice tests are great to see where you stand in your studies, but some people resort to rote memorization and never actually LEARN anything about ham radio.