Here is a resourceful website Theology on the Web maintained by Rob Bradshaw. I came across it (HT: Jeff), surfed around and found a host of many other biblical and theological resources that has links to articles by many theologians (e.g., Tillich, Schaeffer, Rahner, Bonhoeffer, Bultmann, etc. ).  Some link only to books on Amazon but some link to numerous PDF articles like F.F. Bruce. Check it out.