We have trial access to Oxford Bibliographies Online (OBO) until 5/29/10.  According to Oxford, OBO is

an entirely new research tool for the social sciences and humanities. A scholar-curated library of discipline-based subject modules, OBO is designed to help busy researchers find reliable sources of information in half the time by directing them to exactly the right chapter, book, website, archive, or data set they need for their research. Each entry is a selective guided tour through the key literature on a topic, receives multiple peer-reviews as well as Editorial Board approval, and is designed to facilitate a research experience with no dead ends.

Subject modules currently available are Classics, Criminology, Islamic Studies, and Social Work.  Your feedback is welcomed.