Not sure how "basic" you are looking for...below showed up in a email received from recruiting service recently. Good luck.
Organization of the letter
Salutation: Address each letter personally—e.g., "Dear Coach Nascimento." Form letters addressed "To Whom it May Concern" actually create a negative impression.
Introduction: State the intention of the letter, that you are interested in playing for his team. Explain why you're interested in his college. Be specific. Coaches will love that you've done some research and aren't just spamming the world.
Self Description: Describe yourself as a player. Discuss what your tendencies are and the responsibilities you have on your team. If you're a team captain, say so.
Accomplishments: Briefly describe your qualifications and most recent awards. You don't have to list all of your accomplishments in your cover letter—that's what your recruiting profile is for.
The Next Step: Promise to follow up on this initial letter with a schedule of your team's games and tournaments. In the meantime, request any standard recruiting materials. Most coaches have general information forms they like recruits to fill out. This helps streamline the deluge of information they receive from prospective players.
Closing Phrase: "Sincerely," "All the best," etc.
Your Name: Type your name below your signature