TWiT.tv has a cargo-hold full of shows free for non-commercial broadcast under Creative Commons License.
Anticipating that I would need programming, I contacted a few podcast producers about their content. They cheerfully said 'yes' to letting me use their material which I thought was great.
I've given serious consideration to producing my own content. What I'd need help doing is finding out what it is people want for their Part 15 station.
For my station I like talking.
One guy talking to himself can be good, two people holding a conversation, phone conversations or TeamSpeak audio conferences, speeches before an audience, interviews, commentary on news or other fields, humor, science, on and on.
The most common programming done by almost everyone is music, but that doesn't impress me because the DJ isn't making the music, he only selects it... I can select my own music.
Thousands of books in the public domain are read aloud and offered free for use at Librivox(dot)org.
Every Saturday over-night KDX Worldround Radio presents "Radio Books" featuring these great audiobooks.
For the 5th week in a row we just presented Part 5 of "The World As Will and Idea", the major philosophy work of Arthur Schopenhauer.
We often bring poetry of Edgar Allan Poe and "On Civil Disobedience" by Henry David Thoreau.
It's good. You should try it.