Since working as an RA for Kieran I’ve been using BibTeX to manage my bibliographic data, and I have amassed quite a set of disorganized bibliographies. While many online services can export references in formats compatible with software like EndNote and ProCite, not many of them, at least in the social sciences, provide support for BibTeX. (RefWorks seems like an interesting possibility in this regard; it looks like it provides some nice BibTeX-compatible features in the form of a web-based reference manager.)
It probably won’t help me get any better organized, but Bibster looks like it could be a neat tool for gathering references. It’s a java application for Linux (loaded right up on my system) and Windows, and it connects to a peer-to-peer network of shared BibTeX-format references. So far it seems built explicitly for computer science-related material, but there’s no reason it couldn’t work with social science references; of course, there would need to be a much larger community of BibTex users in social science. The standard set of peet-to-peer problems are present: Availability is likely to be an issue, as is accuracy, but at least the bibster network won’t have washed up superstars seeding the network with false data.