This web site is for people studying for one of the popular international ESL exams: IELTS, TOEFL, TOEIC and Cambridge English exams. There are also some practice tests for PTE Academic and General as well as Michigan and SAT. The site has information about the tests, and you have to click through some of that to get to the practice test parts.
Detailed information about the scoring information for the TOEFL.
This site has a nice free test, with registration, and quite a few available for purchase.
Learn 4 Good
Limited set of practice exercises.