Google Scholar have been launched yesterday !
This is one of the good Google move, without the dollar sign place at first objective, for now. It also offer some new informations to us with the crawl in the invisible Web. The citations ranking results are also a very good choice over the PageRank.
This project have probably germinated at Google with the Open WorldCat program in january 2004.
It is weird that nobody at Yahoo wake up and make something like that after their index got more than 2 time the size of the Google index of Open WorldCat ?
Here two good reviews of the Google Scholar : The librarians view and the search engine specialist view.