EnglishOnline.net: Offers free writing tips, and explanations for ESL / EFL students and teachers. Information on essay, business, and technical writing.
Text Content Analysis Tool: Analyse text content. Gives you statistics about word count; unique words; number of sentences; average words per sentence; lexical density; and the Gunning Fog readability index.
World-English: English exercises about business English, a guide to write a basic business letter or CV, a financial vocabulary quiz and a list of computer vocabulary.
WritingForResults.net: A free business writing site. Guidance & templates for those who prepare briefing notes, briefing books, policy memos & policy papers for cabinet ministers & senior executives.