For those of you who are interested in the "historical" Judas, a new tradebook by Continuum has just been released on this subject: Gary Greenberg, The Judas Brief: Who Really Killed Jesus? Mr. Greenberg has his own website and blog.
Mr. Greenberg reassesses the Gospels and their sources and generously references ancient literature beyond the NT in order to recover what he has identified as the genuine story of Jesus' arrest and death from gospels that have rewritten that history. He argues from these sources (and his own re-envisioning of events) that the Jewish authorities did not want Jesus put to death, but acted to save him from the Romans, particularly from Herod Antipas and the Herodians whom Greenberg identifies as the ones who wanted Jesus' movement stopped just as they had wanted the Baptist movement stopped.
Within this larger purpose, Greenberg addresses the question, "What do we really know about Judas?" He argues that the gospel writers created the evil Judas, by rewriting his story because of his involvement in the negotiations of Jesus' voluntary transfer to a Jewish delegation which was to protect him from Rome. As Jesus' most trusted disciple, Judas negotiated his "handing over" to the Jewish authorities, a detail that later became understood in the tradition as Jesus' betrayal.
In the end, Rome had its way, and Jesus was arrested and killed by Pilate and Herod.
The book is very accessible in terms of the manner in which it reads and is well-argued, reflecting a revisionary examination of the ancient literature. It deals head-on with many of the problems that have troubled scholars for years, including the difficult and inconsistent stories of Judas Iscariot, the involvement of Jewish authorities in Jesus' death, and the increasing tendency of the gospel authors to find ways to exonerate Pilate.
The book also shows just how difficult it is to recover historical information from the gospels, since the historical memory has been so affected by the contemporary theological needs of the authors of the gospels. The bits and pieces that we can recover often don't make sense on their own, and so require that we speculate about what might have happened to make sense of the pieces. Greenberg offers in The Judas Brief one way to reassemble the pieces.