To get admission into a teaching esl doctoral program, you must have a masters degree in a related area. Most universities would have a GPA cut off as well, somewhere around 3.0. You will also be required to submit around three letters of recommendation, a sample of written work in English and recent GRE scores. If you are an international applicant, you must also submit your TOEFL scores. Keep in mind though that every university will have its own admission policy.