http://www.cerebrals.org/jcti/ is supposed to be one of the best tests online.
On the untimed test.
On the timed test. 66 questions in 25 minutes. Results sent by email.
General Culture Fair Intelligence Test
IQ = 40 (95% Confidence Interval = 38 - 54)
Raw score (number of correct answers out of 66) = 20
My non verbal ability is poor and I never do well under pressure.