Free reference management software

I was finally cleaning up (er, starting to clean up...) the stacks of papers on my desk, read and half-read, and started to experiment with Zotero, a pretty promising free reference management system. In the past, I have used Endnote, which works perfectly, but since I work on two computers -- one at work, the other at home --, it's kind of a pain to coordinate the two reference files. The Zotero creators at GMU at least promise remote library syncing for the future. Let's see. So far, Zotero works if I type in references, but its import facility does not work with some of the research databases I use. Still, it's a free reference management system, and therefore should be of interest to some of my undergrad students who have already spent enough money on textbooks...

Now, fiddling with Zotero, I remembered that a couple of years ago I had experimented with a reference database system called CitULike, also free and completely online. The neat thing with this one is that it pools the references that users enter, somewhat like del.icio.us, which means that some references you would type in are already present. CiteULike lets you export references in Endnote and BibTeX format, which is fine for me, as I write most of my papers anyway in LaTeX. And for people who want to save some money, or students who expect to write only a handful research papers in their life, the combination of the two programs could make life easier.

UPDATE:
Just as I was writing this, a Zotero update came in. Tagging is easier now, it seems, a couple of database translators have been fixed, others have been added. Alas, importing references from EBSCO still doesn't work for me (and this means that I have to type in recent APSR articles). However, (I could have thought about it earlier,) CiteULike works perfectly with Zotero. I can input my references into CiteULike (if they're not already there), and when I need them I just suck them into Zotero (or save them as BibTeX). Not bad.