The suit was filed in U.S. District Court in Las Vegas.
The complainant is the owner of many registered trademark for "New York-New York",registered with the United States Patent and Trademark Office.Therefore,New York-New York Hotel & Casino contended that Ronnie Katzin's domain name is confusingly similar to its trademark.
Moreover,it seems that "When Internet users click on the banner,they are redirected to a website enabling them to book hotel reservations at Plaintiff's New York-New York Hotel."
"Defendants used and are using in commerce the mark New York New York Las Vegas Hotel &Casino in connection with a website that provides links to online reservations for Plaintiff's New York-New York Hotel as well as competing Las Vegas hotels."

You can find here the lawsuit . http://media.lasvegassun.com/media/pdfs/blogs/documents/2009/11/09/nyny110609.pdf