Miscellaneous

BBC Learning English 

Does not contain any immediately usable information for academic writing but is a good all-round interesting Learning English site. 

British National Corpus

A very simple-to-use corpus where you can find how a word or phrase is used in practice and how frequent it is in the corpus. 

Lextutor

Contains an array of lexical tools, the most useful of which is a concordance programme which allows you to key in a word and find out how the word is used, for example what kinds of words are frequently used immediately before or after the keyword. 

Academic Earth

Online video courses from leading universities on a variety of subjects.