zotero
Zotero, a Firefox extension for managing research sources, has announced the release of Zotero 1.5 beta. I've heard good things from those who use Zotero. This major update adds some nifty synchronizing and automatic backup. The next step after this for Zotero, I believe, is adding sharing capabilities.
By the way does anyone know what happened to arXiv on you harddrive? It's not been updated in over a year, which is a shame. Personally I find the arXiv's lack of publicity accessible methods for obtaining the full text kind of a bummer. There is so much fun you could have given the…