Remember that, fundamentally, APA prefers that writers employ a "signal phrase" to introduce a source, whether it be from a periodical or a phone interview. A signal phrase is another way of giving a reader a heads-up that the information to follow originates from someone besides the writer.
Introduce the source at the beginning of a paragraph and classify the phone interview as "personal communication," along with the date of the interview.
Cite the communication in one of two ways: "Cunningham (personal communication, July 4, 2011) made a compelling case for the Democrats' budget plan" or "One pundit made a compelling case for the Democrats' budget plan" (J. Cunningham, personal communication, July 4, 2011).
Take note of the fact that personal communications, including phone calls, do not have to be included in the references. This is because, unlike books and other written sources, phone calls are not as inherently "traceable" and, thus, capable of followup.