Writefix

This site by Enda Toumey, an Irish teacher who has been teaching for about 27 years in Ireland, Zimbabwe, Saudi Arabia and the UAE, is a fantastic open resource aimed at people who are learning English and taking the IELTS or TOEFL exams. 

It is divided into several parts:

1. How to write Argument and Opinion IELTS essays and lots of example essays;
2. Writing about Graphs and other essays (Problem and Solution, Cause and Effect);
3. Speaking for IELTS Speaking and PET Speaking tests; and
4. Your IELTS essays! A place for you to upload your IELTS essays and help other people with their writing.

Lots of other links and activities are provided.

http://writefix.com/
You can also visite its YouTube channel: http://www.youtube.com/user/mrwritefix