My sample ielts writing blog: http://sampleieltswriting.blogspot.com/
full exam: http://www.mediafire.com/?4jt21gxpnarmomj
This series will help you a lot because it was extracted from the real ielts test. However, I think that it is harder than the real IELTS Test :), but it still be a good source for online IELTS practice :)