We have been adding to the online library of presentation videos and currently have 12 interesting videos available on our Presentation Video page. More recently, we have made audio streaming available for each of the presentations for times when you only want to hear the presentation. On computers, the audio file can be downloaded (usually by right clicking) and added to your music library, as well (e.g. iTunes), and then synced to your smartphone or tablet if you want to listen to them without streaming them online. Some (non-Apple) portable devices may be able to download the audio files directly.
We will continue to add content as it becomes available.