Dear Sir/Madam
I am (include details about name, educational qualifications, college etc). I am writing this letter for (state the post, job or the specific internship for which you are applying).
I am enclosing a copy of my resume for your review. I shall be glad at the opportunity of working for my internship in your office. I shall appreciate if you consider my application for an internship.
I shall call you in about a week to discuss the internship, and arrange an interview at your convenience. Thank you for your time and consideration.
Sincerely