To listen to a sermon on your computer:
Select the sermon you wish to listen to from the Archives.
Press play (the speaker icon) and enjoy.

To download an mp3:
Select the sermon you wish to download from the playlist.
Press the download (mp3) button.

To Subscribe to the Podcast:

Go to http://sermon.net/rss/nordmeyerk/main

Click on Subscribe in itunes in the lower left.