A terrestrial station is land based and geographically restricted. Internet Radio is heard throughout the world and has far better opportunity for national and international advertiser, guests and listeners.
Which one do you think is a really better opportunity? That's right. Internet Radio. We are the wave of the future and that's why terrestrial stations are hurting terribly. Stay focused on Internet and within just a few years, Internet Radio will be the only RADIO.
This is really too general. If you just mean music, its a mechanical process of downloading the ShoutCast! software, installing it, and buying bandwidth. I think ShoutCast is much cheaper than Live365.com. The big thing you have to think about is how much content you can keep on the audio server. Most of them have draconian limits (like about 10 hours) or you have to pay through the nose for storage. The cheapest mechanism seems to be to keep the MP3s local on your own computer (which is on 24 hours/day) and stream it up as needed on the ShoutCast! server that you rent.
Pick a niche is right. To be successful, you have the listeners. That should be the aim of every host... growth of listenership. I have the niche of Law of Attraction, Conscious Creation, etc., etc. My numbers have grown so high that I am a benefit to my advertisers, to my guests and especially to my listeners.
Check out my site: www.lawofattracttalkradio.com