In the text of the paper, this source would use the author's last name if no other sources by that author were in the Works Cited section, like this (Sanders). If it were an anonymous web page or article in print, you would use the first significant word in the title, which would be what the readers would see in the left margin when "Sanders, Arnie" was gone, like this ("Citing"). Note that "Citing" is in quotes because it is part of an article title, so the reader does not look for a Works Cited source whose last name is Citing. If you used several sources by Sanders, you would distinguish them in the in-text citation by using the first significant word of the title after the author's name like this (Sanders "Citing"). If the article were paginated, you would add the page number last, like this (Sanders "Citing" 5).
Sanders, Arnie. "Citing Internet Sources: Use Your Handbook and Style Sheet; Citation Logic." English 105.015, Spring 2005: Academic Writing II. Viewed February 11, 2008. Available at http://faculty.goucher.edu/eng105sanders/citing_internet_sources.htm.