Knowing the academic bent of Troppo readers, I thought I would advise that Google has a new offering – Google Scholar.
The aim is:
Google Scholar enables you to search specifically for scholarly literature, including peer-reviewed papers, theses, books, preprints, abstracts and technical reports from all broad areas of research. Use Google Scholar to find articles from a wide variety of academic publishers, professional societies, preprint repositories and universities, as well as scholarly articles available across the web.
So there you go.