Found this as a link from SemanticBlogging.org, which is itself described in an article in this month’s CACM on the Blogosphere and also uses tags to label postings in collaborative ways…
CiteULike: All about CiteULike
CiteULike is a free service to help academics to share, store, and organise the academic papers they are reading. When you see a paper on the web that interests you, you can click one button and have it added to your personal library. CiteULike automatically extracts the citation details, so there’s no need to type them in yourself. It all works from within your web browser. There’s no need to install any special software.
Because your library is stored on the server, you can access it from any computer. You can share you library with others, and find out who is reading the same papers as you. In turn, this can help you discover literature which is relevant to your field but you may not have known about.
When it comes to writing up your results in a paper, you can export your library to either BibTeX or Endnote to build it in to your bibliography.
CiteULike has a flexible filing system, so you actually stand a chance of being able to find that article that you stored a few months ago when you need it.
Only links to the papers are stored, the papers themselves stay in archives like JSTOR or PubMed. At the moment the database is dominated by biological and medical papers, but there is no reason why, say, history or philosophy bibliographies should not be equally prevalent. The system currently supports: Association for Computing Machinery (ACM) portal, American Meteorological Society, arXiv.org e-Print archive, CiteSeer, IngentaConnect, JSTOR, MetaPress, PLoS Biology, PubMed, PubMed Central, ScienceDirect, but more systems will be supported soon.
CiteULike is a free service, and will remain that way. You will always be able to manage your own personal library, and view other libraries on the site at no charge. The central database is backed up every fifteen minutes, and the information in your library is safe and secure.