"The basics of good business letter writing are easy to learn. The following guide provides the phrases that are usually found in any standard business letter. These phrases are used as a kind of frame and introduction to the content of business letters. At the end of this guide, you will find links to sites that give tips on the difficult part of writing..."
Business-to-business letters are letters that businesses send in "normal" business situations, including internal correspondence. Business-to-customer letters are defined as typical letters that businesses send to their customers under normal operating circumstances.
Although this is a commercial site, there is a lot of specific useful information for all types of letters: thank you letters, letters of resignation, sales letters, cover letters, etc.
From the Purdue University OWL (Online Writing Lab).
This resource covers the parts of the basic business letter and provides three sample business letters. The resource is organized in the order in which you should write a business letter, starting with the sender's address if the letter is not written on letterhead.
