A cover letter is a letter that covers whatever you mail to someone. It explains or identifies what it is you are mailing. The most commonly talked about cover letter covers your resume. It explains how your resume fits the job description of a job you are applying for.http://www.quintcareers.com/cover_letter_basics.html
Cover letters are also sent with everything else we encounter in the business world. Examples are disputed bills, a flyer that we want printed, or a legal paper that the recipient needs to sign. A cover letter gives our account number, our address, our phone number, and any other details that will help identify what we are mailing. A cover letter increases the chances that what we mail will be handled soon and correctly.http://www.mobar.org/8e648ae7-b426-4287-aa23-89a2fbecd82a.aspx
Tips For Writing a Resume Cover Letter
Before you begin writing a resume cover letter, get the job description (or at least a vacancy description) for the particular job you are applying for. Do a little online research on the company and the job. Be sure you understand what the company does, and what the job duties are. Tailor your resume to the job description, making sure to include related experience and education. Write a new cover letter for each job you apply for. Tell them why you want this particular job. Show them why you would be great at this job.http://askamanager.blogspot.com/search/label/cover%20letters
For more in depth advice on writing a resume cover letter, see How to Include Salary Requirements in a Cover Letter.