A cover letter for a job application is a personal statement addressed to the hiring manager that highlights the applicant's attributes that can be beneficial to the future of the company. A compelling cover should grab the attention of the hiring manager, giving the applicant an edge over others in the hiring process.
A cover letter should highlight the personality of the applicant, .
state why the applicant is interested in the position, indicate the applicant's experience in the field and provide other relevant information.
While a cover letter repeats materials already found in the resume, it should not be too factual. Cover letter's should be formal, but they should also draw in the reader to increase the chances of a callback.
More Reference Links: http://www.career.vt.edu/JobSearchGuide/CoverLetterSamples.html http://owl.english.purdue.edu/media/pdf/20080218121324_723.pdf