Many of my peers make an inexcusable mistake of thinking that a Cover Letter is an artifact: in old times of applying to jobs via mail or fax, it made sense to include one with your resume, but now, when you either click "Apply" button in the job board ad or send an email, it's not needed. Lazy and wrong! It is true that the cover letter most likely will not make a difference in the first resume screening. However, if your resume gets into the second round, a good cover letter will compliment it and make you stand out.
Here is a link to AOL original online article. It is written by a recruitment professional and has the most concise and comprehensive outline of what must be included in a contemporary cover letter. You will still need all your talent to find the right words and present yourself in the most impressive way, but it is a good start.
The Frustrated CFO 