Try this site for MLA citation rules:
http://www.liu.edu/cwis/cwp/library/workshop/citmla.htm
Here's what they say about websites:
"Websites: include the title of the web page, the name of the entire web site, the organization that posted it (this may be the same as the name of the website). Also include the full date the page was created or last updated (day, month, year if available) and the date you looked at it. "
In other words, I think it is okay if you cannot find an author's name. As it says in the MLA rules (which are the standard everyone uses), you may use the name of the website itself in lieu of the author's name.
Another thing: see if there's a "contact" area of the website, and email them asking who the author was. I'm sure they would be glad to answer that in order to get credit for it.
Good luck!
