Speaking
SharedTalk - Free language exchange website by Rosetta Stone: email, text chat, and voice chat with people from around the world in any language. You can help English speakers learn your language and they will help you.
Writing
Lang-8 - Free language exchange website: write in English and other users will correct your writing. You must also correct other people's writing in your language.
Reading/Listening
NPR - America's equivalent of BBC. They do not have resources for ESL, but they speak very clearly and have many news stories with audio and written transcript so you can read while listening. Good American English practice for advanced English learners or people from an English-speaking country who have trouble understanding the American accent.