Jobs in academia -- either teaching or research -- generally require a statement of interest instead of a standard cover letter during the application process. If you're applying for a teaching position, your statement of interest might be provided to every member of the selection committee, so ensure that it's broad enough to capture the interests of readers who have different perspectives yet specific enough to know that you're interested in the position with that organization and not just any organization.
Review the Requirements
Read the position qualifications to determine what prospective employers want to see in your statement of interest. Many university employers are specific about the information they want applicants to share in the statement of interest, such as teaching philosophy, research interests and teaching methods. If you have a list of requirements or specific questions to answer in your statement of interest, highlight them and prepare draft responses to those items. It could be helpful to review the bios of professionals in similar roles, such as other professors or researchers in the same department. Peruse the school's website for information about the department and potential colleagues.
Determine why you're interested in the job. It may be a stepping stone to your ideal career or because you've always wanted to work for the institution. For either answer, you must have idea of what you hope to accomplish at various stages in your career and in-depth knowledge of the school or research organization and its appeal. Give thought to what you will contribute to the organization; employers want to know what you bring to the table and a statement of interest should address your interest with equal attention as to what the institution will gain from hiring you.
Format the Draft
Statements of interest aren't exactly cover letters -- they're supported by substantive information about the candidate's qualifications and the organization. You can't write a skeleton of a statement of interest and tailor it to the job like you can cover letters for certain jobs. Resist the urge to copy a simple cover letter as the basis for your statement of interest. Use a narrative format instead of the typical business letter format for a statement of interest; your transmittal letter will contain the information you would typically include in a cover letter, such as your contact information. This format provides enough space for at least four to five solid paragraphs to demonstrate your interest in the position and connect your qualifications to the job.
Food for Thought
Avoid merely skimming the surface of your qualifications and interest in the organization. With the extra space, you can afford to spend a full paragraph showcasing one or two of your qualifications that are particularly useful or salient to the organization's goals. For example, if you're applying to a research foundation looking for statisticians with an interest in demographic changes, elaborate on your expertise in multigenerational populations and predictions related to population growth. If permitted, attach copies of relevant work or publications on a subject matter in which you excel.