According to the "MLA Handbook for Writers of Research Papers, 7th Edition," you don't need to include a website's author or publishing date unless the information's available.
In your references list, enter an open quotation mark, list the name of the page where you found the article followed by a period, and then enter a closed quotation mark. Italicize the website's name followed by a period. After the website name, list "n.p." if no publisher is available, and "n.d." if no date is available. Enter the word "Web" followed by a period, and enter the full date you visited the website by day, month and year.
In the references list, a complete citation should look like this: "Office of Teaching Initiatives." NYSED. New York State Education Department. n.d. Web. 6 May 2013.
When citing a website with no author or publishing date in-text, in parentheses, cite the first item that appears in the references list entry exactly as it appears. MLA doesn't require paragraph or page numbers. If you are citing a full Web page and not a specific article, use the website name or partial URL. For example: "New York State Education Department" or partial URL NYSED.gov.
An in-text citation looks like this: Prospective teachers can apply for certification online ("Office of Teaching Initiatives"). In the absence of a Web article, an in-text citation looks like this: Many New York teachers apply for certification online (New York State Education Department).