Start the entry on the references page with the speaker's last name followed by a comma and then the first name, very much like you would for the author of an article or book: Smith, Sam.
Write the title of the presentation inside quotation marks, placing a period at the end of the title inside the quotation marks: "For Whom the Tell's Bold."
List the name of the conference or class, or the sponsoring organization if the speech had no name, followed by a period: Living Poetry Lecture Series.
Put the city and state where the speech was given next, again followed by a period: Denver, Colorado.
Include the date of the presentation at the end, giving the date, abbreviation for the month and four-digit year with no punctuation between and ending with a period: 22 Oct. 2010.
Cite within the text using a signal phrase with the author's last name with the year of publication in parentheses just as you would for other sources: According to Smith (2010), . . .