Are IELTS past tests available for students preparing for the exam? I want to know a way to find past IELTS questions. If they are available freely?  
Are there good exams for all modules? (Specially Listening)
You may use the books available in which some preparation exams (sample tests and past tests) are published and you can study those exams and sample tests. Some of these books and preparation materials are available in How do I prepare? page on IELTS official website, Cambridge English Exams and IELTS books and books about IELTS by other publishers.

If you are seeking for free online sample exams and studying materials, there are some preparation materials for exam available in different websites over the net, which you can find by a simple search.