Dr. Douglas Groothuis has an apologetics course consisting of 44 audio files. Although this can be downloaded one by one on the Ultimate Apologetics MP3 Audio page, now you can download them as a complete batch via RSS Feed here or add them directly into iTunes with one click here.
• RSS Feed / iTunes 1-click podcast
You may also be interested to check out the table of contents of Groothuis' upcoming apologetics book What Matter Most. His blog is here. More Doug Groothuis resources here.