Is there a limit on the amount I can have uploaded to my Media Library?
There is a 10GB limit
What types of media can I upload?
MP3 (Audio) or MP4, MPEG, MOV (Video)
At what rate should my audio files be encoded?
MP3 files must be encoded at a bitrate of 48Kbps or less.
How do I have my podcasts appear on iTunes?
Here is ITune’s how to guide on this: http://www.apple.com/itunes/podcasts/specs.html