According to a Times article, scholars have found a "Gospel of Judas," an ancient Gnostic text defending Judas' betrayal of Christ:
Unlike the accounts in the New Testament Gospels of Matthew, Mark, Luke and John, the anonymous author of the Gospel of Judas believed that Judas Iscariot alone among the 12 disciples understood the meaning of Jesus' teachings and acceded to his will. In the diversity of early Christian thought, a group known as Gnostics believed in a secret knowledge of how people could escape the prisons of their material bodies and return to the spiritual realm from which they came.
The complete article has more information.
UPDATE: A fine article from the S.F. Chronicle, with some pictures.