Two websites give extensive access to works by Kierkegaard and secondary literature about him. SKS.DK has a large collection of the printed writings in Danish, including all of the major classics such as Enten Eller, Begrebet Angest and Opbyggelige Taler, while Kierkegaard Resources World Wide, though in need of updating (the site was established back in 2004 by Dr. Julia Watkin of the Howard and Edward Hong Kierkegaard Library at St. Olaf's College, Minnesota), has links to many monographs, research papers and other documents, including keys to the philosopher's Gothic handwriting, and to his abbreviations (pdf) and spelling (pdf).
Freely accessible online English translations of Kierkegaard are rather harder to find, though the Internet Archive has a copy of the Alexander Dru translation of the Journals, and also of L.M. Hollander's translation of several works, including Fear and Trembling, Preparation for a Christian Life and The Present Moment.
The English translation of Kierkegaard still seems to be something of a controversial area, and it may be for this reason that most of the out-of-copyright translations still apparently remain undigitized in Project Gutenberg and other online libraries. It would be interesting to know more about this, if anyone has details.
See also in this blog: Herder and Hegel