Jorum - jorum.ac.uk
Accessible to anybody, Jorum is a JISC-funded development which serves to collect and share learning and teaching materials, allowing their reuse and repurposing. The materials available are not restricted to English language materials but cover a huge spectrum of topics, providing alternative teaching materials for higher level students.
The site allows you to find thousands of free learning and teaching resources, search by file type, Institution and share your own resources simply and easily via social media tools (Twitter, Facebook, Delicious).
Aimed perhaps more towards higher-level native speakers, the site nonetheless provides useful resources for ESL teachers and higher-level students.