The following is a link to Berkshire Hathaway's website, in particular, Mr. Buffett's Letters to Shareholders from 1977 on:

Warren Buffett's Letters to Shareholders

Even if you are not business-oriented, Mr. Buffett's annual Letter to Shareholders is a great lesson in writing because of his clear, concise and easy style.

If you are business-oriented, then his letters are a must-read. They provide marvelous insight into how informed business decisions are made. Moreover his letters showcase Mr. Buffett's special knack of breaking down a complicated topic into bite size chunks that a layperson would understand.