Conduct your interview and take notes.
Contextualize the interview in your paper. If you embed a signal phrase using the interviewee's name, the citation will require less information. After the quote, put the words "personal communication" in parentheses, followed by the exact date of the interview. Here is a fictionalized example: When interviewed, H. Thomas Expert said, "This is a quote" (personal communication, August 30, 2010).
Add the interview subject's name to the parenthetical citation, if a signal phrase is not employed. Abbreviate the first name, and use the last name. For example: This is a sentence using interview material (R. Last Name, personal communication, August 30, 2010).
Do not include the interview in the reference list at the end of the paper.