For a few years now I've been listening to a program called the "White Horse Inn" hosted by four guys of various Christian denominations but all of a Reformed perspective. You can listen to their shows on Oneplace.com (not everything at oneplace.com is as good as WHI though.) Till recently one had to pay to download their archived shows on mp3, but now it seems that the shows are free with registration at oneplace. This means one could 'podcast' several shows at once.
I highly recommend this great resource. Also, as Phil Johnson noted, John Piper has a series on the life of Athanasius, describing the Arian debate. This is of particular interest to me, as I just experienced a lengthy email discussion with one of Arius' modern offspring. I may blog on this discussion sometime in the future.
I also want to send a shout out to centuri0n who has turned out to be more than your typical Christian trinket seller and to the Calvinist Gadfly, that defender of the Calvinist banner... semper fi my bruddas!