You can export the podcast audio from FCP very easily. In the export window, go to to the settings tab and choose “Audio Only” from the drop down menu. Your codec settings will be replaced with audio settings (mp3, AIFF, WAV). This will not take long at all compared to the video, and you can even have it set to do this while the video is exporting.
As for the video, unless you need to have a clean Master file saved, use the Vimeo preset like Bret said. It will even save you the trouble of uploading the video to Vimeo.
Jonathan Sutton
Video Editor
The American College Video Studio
https://vimeo.com/theamericancollege