Biblical Training is a fantastic website with many audio files available for free download. You'll have to create an account but the content is worth it. These lessons cover a variety of topics including, "A History of Philosophy," "Church History," "Christian Ethics," etc.
Be warned, some of the teaching is not mosher (Mennonite Kosher). Some podcasts contradict others. The professors don't all agree. You'll notice most follow the Calvinist bent. One professor suggested that if hypothetical Eskimos didn't have a word for "sheep" you should use the word for "baby seal" when translating ... which is possibly the most absurd thing to come out of evangelicalism since televangelists.
Ravi Zacharias International Ministries has vast podcasts available to download via the iTunes store and on their website. Personally, these began my journey into apologetics. Listening to these podcasts, I was finally confident that my faith was defensible in the secular world on "secular terms." I ""'d that last bit because some people get finicky about terminology. I might even say I learned that Christianity required a lot less faith than I first thought, but that would require a lot more ""'s.
Ryan Reeves is a professor at Gordon Conwell University. He has a PhD in church history from Cambridge University. This gentleman put together some fantastic lectures on church history and they're on youtube. The first in the series I've embeded here because it was either that or his mug. I chose the video. I also recognize that we've slightly cheated and put videos in the podcast section.
R.C. Sproul is a fairly well known preacher and teacher. His most valuable material can be found in his lectures on topics from Catholicism to theological topics with fancy names that I've forgotten. He also has material on youtube. I was originally impressed with this teacher because his lectures on Catholicism are surprisingly fair and unbiased even though R.C. Sproul is not Catholic.