Monster.com offers a choice of several cover letters formats for use when submitting a resume to a prospective employer. Their options include cover letters for sales, education, engineering, information technology and administrative positions.
In addition to offering various specialized cover letters, Monster.com also provides advice on how to effectively use a cover letter as part of the job application process.
For additional cover letter options try the About.com careers section. About.com provides several customizable cover letter choices including formats for targeting a specific job. They also offer generalized cover letter templates for use when applying to several types of positions.