Never use a generic cover letter with only: "To Whom It May Concern." You would be much more likely to read a letter that was directed to you personally and so would human resources professionals. Do some research to find the name of the individual in charge of human resources. The name is usually found within the body of the job description, and if it is not included, visit the company's website to find the name of the Human Resources Manager
Creating a great telecommuting cover letter is critically important to your potential for getting the job! It is the very first thing a prospective employer sees when you send in your resume, and without a great cover letter, you may be reducing your chances of being noticed.