Where can I find a free legitimate online IQ test?

The short answer to your question is, "You can't." For a "real accurate IQ test" the access to the questions and tasks as well as the answers must be carefully controlled and administered under standard conditions. There are several other technical procedures relating to establishing the validity and reliability of the test that must be followed, too. The best you can do online is to find a test that might give you a rough estimate of your cognitive abilities compared to the accepted benchmarks such as the Wechsler and Stanford-Binet batteries that take well over an hour to administer to an individual. Another option comes to mind: take the Mensa qualification test for a nominal fee (I forget what it is these days). This test is designed to discriminate among above average individuals. There's even a screening test that you can take at home. Here's their website: http://www.us.mensa.org/