yahoo ? did you mean yahoo.com ? I have no idea about it. Because everything was suctomized. Than, as i can see in my experience... nothing free/paid script like that. Maybe if you want to made some script like mini search engine i can help you Hope this help...
if you are looking for yahoo clone with all of it's functions like:- my yahoo yahoo 360 video,yahoo music.yahoo yahoomail and a lots lot lot and a lots more then I am ready to make a script for you @ just $1 million...LOL You will never get it's clone ..you will need to make a customised one if you have a lot and lot money.
there is a clone looks like yahoo with the name raja or something like that.. you will find it here nulled : http://www.zo0n.com/?oqRnI