The DIY Scholar and others have already recommended Yale's new open course Introduction to New Testament History and Literature with Professor Dale B. Martin. And I am here to recommend it also. (feed)
However, a discussion rose in the Podcast Parlor, because in this lecture Dale Martin made an attempt to frame the origins of Christianity in the Judaism of the Second Temple Period and carelessly characterized Judaism as "an ideology of empire and world domination embedded in [the] scripture, and yet [the] social and political situation was just the opposite." This had some eyebrows raised yet Martin never made any renewed reference in the lectures afterwards to this crude line of thinking.
In stead he is fresh, provocative, clear and at times entertaining. He also stimulated me to refresh two other podcast series on the same subject: Thomas Sheehan's The Historical Jesus (feed) and Philip Harland's Religions of the Ancient Mediterranean (feed). These two make for a wonderful addition and parallel coverage of the same subjects, each in their own way. It needs to be noted though that Sheehan's podcast is rather old and is not up to today's audio standards and also offers the chapters in the wrong order. It is still a great series, just check with the syllabus (which is part of the feed) in order to identify the right order.