There is a preselected set of stations you can set up without the API.  For those, you have to register the bunny, then on the burrow web page (My Nablife, choose the music category under Nabaztag's services.  Sky networks' modern jazz, urban jazz, and smooth jazz stations are available.  I think if you register for these, you can then use the voice command to call them out by name.

For other stations, you'd have to send the command through the API, and the API does not support any voice command interaction, or button input.  You'd have to select the station from the program running the API on your PC, or have your PC API application check the ear position, and use the ear position to select the station from some preset list. 

Streaming stations usually use a .pls format (a playlist of mp3 url's), and at least one of these (WXPN) that plays fine on ITunes won't seem to work on the rabbit, so I'm not sure all stations work.  I seem to remember reading that the MP3 feed needed to be at a certain bit rate as well.