I dont know much about them other than what I heard on the recent World in your ear prog on BBC radio 4
Basically it is a radio programme that is downloadable that you can subscribe to and recieve on a regular basis.
The original concept was to give iPod users something akin to radio programmes on their favourite topics instead of being tied to corporate radio stations.
Its still down loading stuff off the internet but there are directories where you can find a range of programmes
This format has been taken on board by amateurs and enthusiasts and seems ideal for niche interests who are forever being overlooked by the corporations
Sometime ago I posted a thread here asking for favourite internet radio stations and got a good response which brought some interesting stuff to light
I thought a similar thing would happen with this thread