Although this link has been sitting in the “Archives, etc.” link list in the phonoloblog sidebar for some time now, it’s worth mentioning more explicitly. LingBuzz is “an article archive and a community space for Generative Linguistics. You are highly encouraged to upload your articles – old and new, published or not.”
LingBuzz was conceived/coded and is maintained by Michal Starke. Michal recently implemented a feature that points to papers on other linguistics archives, such as the Rutgers Optimality Archive and semanticsarchive.net.